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July 2022

Perimeter Puzzle
What is the ratio between the perimeter of a circle to that of a square that touch as shown in the diagram?
May 2022

Service Interuption
GoDaddy tanked my site, sorry.
April 2022

Plant a tree
Can planting a tree make a difference?

Mathematician's Card Trick
Guessing from three boxes in one try.
January 2022

NFT Gaming is snake oil
It might be cool technology, but it's totally wrong.
November 2021

Impossible Dart Scores
What scores is it impossible to obtain in darts?

[0-9] digit puzzle
Rearrange the digits [0-9] to make three numbers: x,y,z such that x+y=z.
October 2021

Hamiltonian Path Puzzle
Label the grid 1–49 connecting adjacent edges so each shaded cell is prime.
September 2021

52 card pickup
How many times will you need to pickup a randomly jumbled deck if each time you discard the face-up cards?

Chessboard distances
Minimum number of moves to get to any square.

Bayes, keys, and prisoners
Counterintuitive probability questions.

Inebriated Unlocking
How many attempts to sucessfully unlock a door?

Venn Diagrams
What is the overlap between US States and Chemical Elements?
August 2021

Missile Command
What is the probability of survival if each missile battery selects its own target?
July 2021

Why are windsocks striped?

Stopping Traffic
How much energy is wasted to allow you to cross the road?
June 2021

The sledgehammer and the nut
I should not have written code.

Horse Jumping
How many different ways can you configure seven fence components?

Recycle Logo
Are you sure you are looking at the correct logo?

Fifty Shades of Gray (Socks)
How many socks do you need to take?

Flying Cars
Stop trying to build flying cars!

Containing a one
What percentage of the first billion positive integers contain the digit one?

Rolling, Banking, and Radioactive Decay
What is the expected number of rolls to bank three dice, if rolling a six banks any die, and how does this relate to radioactive decay?
May 2021

Tunnel Escape
Outrunning a train in two different ways.

How to select fair teams
Evenhanded ways to split a group in two.

Twelve Days of Christmas
How many gifts in total?
April 2021

Two Dice, Same Score
What are the chances that your total from a pair of dice matches your friend?

Texas Hold'em Poker
You are more likely to get a Royal Flush than a King-High Straight Flush!

One Billion
Two numbers multiplied that do not end in zero.

Coffee Time Challenge
Two unknowns in arithmetic and geometric progressions.

Missing Something?
Issue with email alert service.

Fly on a Hexagonal Prism
What is the shortest distance between opposite vertices?

Two Presents
Which girl has the biggest present?
March 2021

Ten Switches
Can you open the safe?

How deep is the well?
Equations of motion.

Strictly increasing numbers
How many five digit strictly increasing numbers are there?

Ian and Dog
Overly energetic dog puzzle.

Jessica`s Secret Bracelets
Finding hidden rectangles in beads.

Painted Cube Puzzle
Yet another painted cube puzzle.

Creditcard Number Generator
Generating test numbers.

Coin on an infinite Chessboard
What is the probability a tossed coin will land on a single square?

Romeo and Juliet
How long until the lovers meet?

Buy Me a Coffee?
Help pay for hosting costs.

Six Switch Puzzle
What is the expected number of moves to turn all the lights on?

Soda Can Stability
How much soda should you drink to make your can least likely to tip up?
February 2021

Three Napkins Puzzle
Covering the biggest square table.

Impossible Baseball
The official rules contain an impossible requirement.

Bomb Defusal
Red wire or Blue wire?

Scrabble Racks
Good and Evil starting racks.

The importance of independence
Diversity is better than duplicated competency.
January 2021

The Orchard Game
What are the chances of winning?

What is the best starting hand?

Change One Letter
Transforming words by changing just one letter.

Rolling Two Dice
Are you more likely to roll a twelve before two sevens in a row?

CES 2021
There will be no CES showfloor this year.
December 2020

Present Exchange
How to prove that people exchange mutual gifts.

Alternate d4 labelling
How can you label a four sided die using only one number per face?

Two Decks Puzzle
If you deal from two shuffled decks, in parallel, card by card, what is the probability that at least one pair of cards matches?

My site will now be exclusively dispensed over HTTPS.
November 2020

Gender Identification Puzzle [Update]
A solution with lower expected value.

Gender Identification Puzzle
How do you purchase a pair of chicks with the shortest number of trials?
October 2020

Marble Puzzle
How many blue marbles are there?

Coin Flipping Robot
What happens to the concentration of heads in the room?
September 2020

Milestones in Aviation
Important dates in the conquest of air and space.

Hitting the Sun
It's practically impossible to fire a rocket and hit the Sun.

Miss Shilling's Orifice
Celebrating a brilliant aeronautical engineer.
August 2020

A butt load of work
It probably doesn't mean what you think it does.

There are many ways to skin a cat
Solving problems in different ways (and optimization).

Red, White, Blue coin weighing puzzle revisited
Separating six coins in two weighings - a better solution.
July 2020

Red, White, Blue coin weighing puzzle
Separating six coins in two weighings?

Imposter Syndrome
I am a fraud!

Rocket Science
A beginner’s guide to Astronautics.

Firework Science
A quick look at the ballistics and stability of aerial fireworks.
June 2020

Three d20 betting game
What is the probability that one dice rolls between two others?

Musical Intermission
Over eleven years of blogging!

Social Distancing at the Park
What is the best way?

Gold Cubes
How to fairly distribute cubes of gold.

Toxic Sludge Puzzle
How many people will it take to empty the sludge in an hour?

Second Place?
What is the probability that the second ranked team makes it to the final?

Perfect Roots Puzzle
What is the smallest number that is a perfect square, cube, and fifth power?

Social Distancing Puzzle
How many ways can people sit safely at a bar?

Two Swimmers
Can you work out the length of the pool?

Cut and Restored Checkerboard
If you cut, shuffle, and restore a 4x4 checkerboard, what are the chances you'll end up with a checkerboard again?

Birthday and Free Movie Ticket
Maximizing your chance of winning a free movie ticket.

Chess Tournament Puzzle
Is is better to play a weak or strong opponent more than once?
May 2020

50:50 Sock Puzzle
How many socks do you need to take to have a 50% chance of getting the pair you want?

711 Price Puzzle
Four items whose sum of prices is the same as their product.

One Dice or Two?
How often will one dice roll win over two?

Multi Armed Bandit Game
I wrote another multiplayer game.
April 2020

Three Triangles Puzzle
What is the area of the shaded regions?

Motion Camouflage
Creeping up without being noticed.

Space Miner
I wrote a multiplayer game.
March 2020

Monoliths and Bricks
How could '2001: A Space Odyssey' have been geekier?

Bucket of Dice
How many dice do you have to roll to have 95% confidence you'll get at least one six?

Two sixes in a row
How often does this happen?

Four-of-a-kind in the dark
How many cards must you deal?

Pythagoras Revisited
Interesting fact about the Pythagorean theorem.

What is the probability of dealing a Blackjack?

Toilet Paper: How long does it last?
The relationship between size and consumption.

Sum of Digits
Can you write code to sum up all the digits in numbers 1-N?

Heroic Triangles
Triangles with integer edges and integer areas.

Finding Nemo
How long does it take Nemo's forgetful friend to find him?

Another Painted Cube Puzzle
How many sides were painted?
February 2020

Glass Half Full?
How good are you at estimating a half-full glass?

Giving Back
Want to invite me as a guest lecturer?

Who finished second?
A fun little puzzle created by the NSA in 2016.
January 2020

Gambler's Ruin
How easy (or not) is it double your money in a casino?

Random points in a sphere
How do you generate random points in a sphere?

CES 2020
Notes from my visit to the 2020 Consumer Electronics Show.

Spelling Bee Solver
Solver for the New York Times Spelling Game.
December 2019

The Best Full House
What is the best Full House you can be dealt in Poker? (Warning: You'll probably get it wrong)

String Selfie
Winding a single thread around a collection of pins to make an image.
November 2019

Recovering Source Code Puzzle
What is the fastest way to recover these missing constants?

Wood does not really burn
When you sit infront of a fire, it's not the wood that is burning.

Heavy Hitters Algorithm
How to, efficiently, find the most popular items in a large dataset.

Zeller`s Congruence
How computers calculate the day of the week.
October 2019

Self Similarity
A guest post from Rami Luisto about self-similarity.

Sum Free Sets
How can you arrange numbers into sets so that no two elements adds up to a third?

Four Points Puzzle
How can you arrange four points so that there are only two distinct distances between any pair?
September 2019

Star Polygons
Creating stars from regular polygons.

Venture Beat Article
Thank you to my friend, Dean Takahashi, for writing a moving article about my condition.

Tessellating Regular Polygons
Why do some polygons tessellate and others do not?

Elf Chalkboard Puzzle
If math elves replace pairs of numbers with their differences, will the result be odd or even?
August 2019

Pearl Bracelet
What is the relationship between the diameter of a bracelet and the diameter of the pearls that make it?
July 2019

Video Poker Strategy
What is the optimal holding strategy when playing video poker?

A^B or B^A
Which is bigger: A^B or B^A?

Approximating the Sine Function
How close can we get to approximating the trig function sine using very simple polynomials?
June 2019

Sad News
I have some sad news to share.
April 2019

Word Ladder Solver (Longest Solutions)
Longest solutions to the distinct shortest lengths distinct word ladder problems.

Word Ladder Solver
Transforming words, one letter at a time.

One Trillion Dollars
How long would it take to count a trillion dollars?
March 2019

Optimal Shooting Angle
What is the best location to shoot at the goal from?
February 2019

Uncut Spaghetti
Can you connect each square on a grid with a single thread?

Birthday Paradox Revisited
Looking at the birthday paradox with real data.

Drones and Helicopters
Why are we trying to scale-up drones and not just use helicopters? It’s unmerited!

AIME Math Puzzle
A fun little problem from a past American Invitational Mathematics test.

Christmas Tree Lights
Something weird happens when you wrap lights tightly around a conical tree.

Bogus Science
What is really happening when you throw a cup of boiling water into frigid air?

Ten square units
How can you make a ten square unit square on a chessboard?

How many squares on a chess board?
(and a puzzle dating back to 2002).
January 2019

Cutting a Square Cake
How do you fairly cut a square cake into three pieces?

Square and Arc Puzzle
What is the ratio of the smaller square to the larger square?

Semicircle Puzzle
What is the area of the shaded region?

Multiple Choice Quizzes
Limitations of multiple choice exams (and a potential solution?)

CES 2019
Notes from my annual pilgrimage, and thoughts for the future.

Anagrams made by rotating letters.

2018 Traffic Data
How much traffic does a blog get?

Sudoku Solver
Online Sudoku Solver.
December 2018

Christmas elves puzzle
How many additional elves does Santa need to ensure toys are made on time?

Optimal Picture Viewing Distance
How far away should you stand from a picture?

von Neumann Poker Analysis
Nash Equilibria, and optimal play for simple poker game.

Self Avoiding Walks
How to walk a checkerboard visiting each square only once.

Site Redesign
Major site redesign to support responsive rendering.
November 2018

What are autostereograms, and how do they work?

How big a mirror do you need to be able to see all your body, and what happens to the size of your reflection if you back away from a mirror? Also, what is the Venus Effect?
October 2018

Simple Feed Ranking Algorithm
How to efficiently order lists based on popularity and recency.

Serial and Parallel bulb puzzle
How to connect two bulbs in series or parallel with a switch.

Slot Machines
The psychology of why people love to play slot machines.
September 2018

Overlapping Disks
What is the relationship between the percentage overlap during an eclipse, and the separation of the objects?

Human Fuel Consumption
How many miles to the gallon does a person get?
August 2018

Probability and Tennis
Based on your skill, what is the probability of winning a tennis match?
July 2018

Grazing and Calculus Revisited
Revisiting the optimal grazing field size using a barn and straight section fencing.

Verlet Simulations
Simple physics simulations of cloth and rag-dolls based on Verlet Integration.

Poor Customer Service
Why do companies not understand how poor customer service, whilst seemingly advantageous in the short term, is damaging in the long term?
June 2018

Lucy`s Secret Number puzzle
How can you determine Lucy’s secret number when you only overhear part of her conversation?
May 2018

Six Dice Betting Game
What are the chances that rolling six dice will result in four distinct numbers?

How digital cameras work
And the clever math that turns their color-blind sensors into full color images (plus some bonus calculus and interpolation).

How analog TV worked
The clever technology around how analog TV protocols were created, and why there was an odd number of lines on an old TV screen.
March 2018

Turning Water into Wine
How to turn water into wine (with and without recursion). Calculating Levenshtein distances.

Sock Puzzle Revisited
What is the probability of pulling out matching pairs of socks from a drawer in darkness?

Compound interest and retirement
Why it is critically important to start saving for your retirement as soon as possible.

Nine digits puzzle
Arrange the digits 1-9 to make a nine digit number such that the first digit is divisible by one, the first two digits are divisible by two, the first three divisible by three ...
February 2018

Mathematics of Tape Recorders
The mathematics of tape machines, cassettes, and toilet rolls.

Cribbage Scores
What is the distribution of all possible cribbage scores? (And what is the connection between Cribbage and nuclear submarines?)

Kolmogorov and randomness
What does it mean to be random?

Pancake Numbers
A classic problem involving the optimal way to flip a stack of pancakes into sorted order using just a spatula (prefix reversal). A young Bill Gates co-wrote a paper on this, and his upper bound solution was the best known solution for almost 30 years!

Linus Sequence
A mathematical sequence named after a famous Peanuts cartoon character.

Superbowl Helmet Puzzle
A quick geometry puzzle for a shape that looks (a little) like a football helmet.
January 2018

Moravec's Paradox
Predicting the future is a crap shoot and, ironically, what appears to be hard is easy, and what appears easy, is really hard.

Shortest Crease Problem
A classic problem about how to calculate the shortest crease by folding the corner of a piece of paper (and how most calculus text books get this wrong).

CES 2018
Notes from the show this year.
December 2017

Linked Lists
The basics of linked lists.
November 2017

Incremental means and variances
How to keep a rolling track of the average and standard deviation of a stream of numbers, without having to reprocess the entire set, and minimize the chance of precision loss.

Linear Feedback Shift Registers
Incredibly useful, and efficient, ways to cycle through a range of values.
October 2017

Multi Armed Bandit
What strategy should you employ when faced with a series of parallel experiments that have unknown outcomes?
August 2017

Poor Customer Support?
GoDaddy took one of my websites offline for six months, and only offered compensation of one month of future hosting costs if I were to renew!

The jet plane that shot itself down
The unfortunate incident of the plane that shot itself down.

Van der Waerden Numbers
Colouring sets so there are limited arithmetic progressions.
June 2017

Hexagon Geometry Puzzle
What is the area of the shaded quadrilateral?

Wind Turbine Efficiency
How much energy can we extract from wind?
May 2017

Voronoi Soccer
Who is nearest the ball?

Voronoi Diagrams
Mapping nearest locations.
April 2017

Alphabear Solver
Tool to help solve difficult Alphabear puzzles.

Cake cutting part 3
Episode three of cutting a cake into eight pieces.

Cake cutting part 2
Revisiting the best way to cut a cake into eight equal sized pieces.
March 2017

Cake cutting
What's the best way to cut a cake into eight equal sized pieces?

Three Bag Logic Puzzle
How to determine the contents of a treat bag with a single question.

Cryptogram Puzzle
A cryptogram puzzle using the digits 1-9.

Vestigial trigonometry functions
Trig functions that were popular 30+ years ago, but are rarely mentioned these days.

NSA Easter Egg Puzzle
A puzzle to determine the better strategy to hunt for Easter Eggs in sealed boxes.
February 2017

Interactive Hangman Solver
Online interactive hangman solver.

The Price is Right
What is the optimal strategy for playing the Big Wheel?
January 2017

Crazy Progress Bars
Why do time estimates on progress bars sometimes go crazy?

Radiocarbon dating
How does Carbon-14 dating work?

Centroids of semicircles and hemispheres
How to calculate the centroid of a semicircle, and how this is different from a hemisphere.

Self Driving Cars
Will self-driving cars enable jerks? Will laws have to change?

CES 2017
Notes and thoughts from my visit to CES 2017.
December 2016

Painted Cube Puzzle
A classic puzzle involving cutting a painted cube into smaller cubes.

Analysis of the odds on this classic casino game.

Mathematically, what is the optimal pitch for a roof?
Mathematically, what is the optimal pitch for a roof?

Think slow, think fast
Two simple math problems to which the first answer you give might not be correct.

Freudenstein’s Equation
Deriving a formula for the wheel angles in Ackerman steering.

Ackerman Steering
How, and why, the front wheels of your car turn at different rates.
November 2016

Grazing in a circular field
How long a rope do you need to allow a goat to graze half a circular field, if it is tethered to the circumference?

Lost Car Key Puzzle
Bayesian analysis of lost car keys.

Tangent Length Puzzle
Coffee time challenge: What is the length of this tangent?

Aligned Clock Hands
How many times a day do the Hour, Minute, and Seconds hands of an analog watch align perfectly?
October 2016

6 years and 250 Articles
I've been a blogger for six years and written 250 articles.

Einstein's Spacetime
What is the real explanation of gravity?

Multiple Raffle Strategy
Should you put all your tickets in one drawing, or spread them out evenly?

Champagne Bottles
What are the different sizes of Champagne bottles?
September 2016

Poker odds with wild cards
How do poker odds change with the addition of wild cards?

Poker Odds
What is the relationship between the chances of a poker hand occuring and its rank?

Wire Gauges
Why do wire gauge numbers go up as wires get thinner?
August 2016

Lagrange Points
Orbital mechanics, and Lagrange Points (things most physics text books get wrong).

Moscow Math Olympiad Puzzle
How can you and a friend publicly communicate about cards you are holding without a third person knowing?

Balanced Field Length
What is your best strategy if your plane experiences an engine failure during take-off?
July 2016

Efficient Guttering
What is the optimal way to bend a flat sheet to make an efficient gutter?
June 2016

How things float
What orientation will a square log float in water?

Matter and Neutron Stars
What happens when you compress the space that is inside atoms?
May 2016

Blending independent estimates
How should you combine two independent estimates of age (with different Variances)?

Piano Keyboards
Why are the black and white keys of a piano spaced the way they are?

Bisecting an arbitrary triangular cake
An extension of the cake cutting puzzle from last week.

Bisecting a triangular cake
What is shortest cut on a triangular cake to make two equal sized pieces?
April 2016

Baseball Card Collecting
On average, how many baseball cards do you need to buy to ensure you get a complete set?

Eiffel Tower
Is it true that the air around The Eiffel Tower weighs more than the tower?

Solar Eclipses
What's the difference between a total and an annular solar eclipse?
March 2016

How tall is that tree?
How can you determine the height of a tree without chopping it down?

Two Bingo Ball Puzzle
If you draw two balls 1-75 and keep the highest one, what is the expected value?

National Pi Day
Finding digits in Pi that correspond to their position.
February 2016

Grazing and Calculus
What is the optimal shape for a rectangular grazing paddock?

Two nugget problem
How do you determine the two heaviest nuggets (out of sixteen) in the least amount of weighings?

d20 stopping puzzle
Roll a d20, and collect the value value shown, or pay to roll again?

Russian Roulette
How do the odds of this game change with more chambered rounds?

Six Roll Dice Game
What is the optimal strategy for playing a simple dice rolling game?
January 2016

Hamming Codes
Detecting (and correcting) errors in digital signals.

Defective Circuit Board Puzzle
I have ten circuit boards, and I know exactly two are bad.

CES 2016
Consumer Electronics Show 2016.

Koch Snowflake
Generating snowflakes using recursion.
December 2015

Tricky Geometry
The World's hardest, easy, geometry puzzle?

Weird Number Bases
Will future digital computers move away from binary?

Estimating known unknowns
Can you estimate the number of unfound errors in a document by comparing two independant analyses?
November 2015

Generating mazes with back track recursion.

Golf Balls
How much does the addition of dimples adjust the Volume and Surface Area of golf balls?
October 2015

Cutting a semi-circle
Geometry puzzle about dividing a semi-circle into three.

Go easy on Volkswagen
Yes VW screwed up, but cut them a little slack.

Generating Fibonacci Numbers
What is the best programatic way to generate Fibonacci numbers?

Lychrel Numbers
What is the longest known delayed palindrome?
September 2015

Gravity Variations
How much does your weight vary as you move around our planet, and why?

Business Execution
Ideas are cheap. It's all about the execution.

Twenty Peg Puzzle
How do you determine if four points make a square?

Becoming an adult
At what age, legally, do you become an adult?

Langton's Ant (and Life)
Simple cellular automatons.

Anti Counterfeit Measures
Interesting patterns printed on most banknotes to deter counterfeiting.
August 2015

Telephone Keypad Design
Why are the push buttons on a telephone arranged the way they are?

Chicken nugget numbers
Chicken nugget numbers, and how to make optimal change.
July 2015

Carnival of Mathematics #125
Carnival of Mathematics blog-roll, episode #125

Congruent Rectangles Puzzle (trig solution)
A trigonometric solution to last weeks geometry puzzle.

Congruent Rectangles in a Square Puzzle
A geometry puzzle that, at first glance, appears to have not enough information to solve.

Fan Direction
If you are trying to cool a room with a fan, is it better to suck or blow?
June 2015

Space Needle Climb
I'm climbing the Seattle Space Needle to raise money for cancer research.

Roulette Wheel
Why are the numbers on a roulette wheel distributed the way they are?

Carnival of Mathematics
I will be hosting the August 2015 edition of the Carnival. Do you have any interesting facts about the number 125?

Standard Deviation Puzzle
What number can you add to the set {1,2,3} so that the standard deviation remains the same?

The Pardoner's Puzzle
Can you connect sixty-four towns with eight straight lines, and what is the connection with Harry Potter?

Five Circles Puzzle
Is it possible to draw five circles over a grid of 5x5 points so that at least one circle passes through every point?
May 2015

Buffon's Needle
Calculating Pi by dropping needles on the floor.

Poincaré conjecture
Poincaré conjecture, Topology, million dollar prize and pretty pictures.

Clover Leaf Geometry Puzzle
What is the area of the shape described by the overlap of four inscribed semi-circles in a square?

Running Track Geometry
Why are running tracks oval in shape, and why do runners start from staggered positions?
April 2015

Geometry Puzzle (update)
Update on last weeks geometry puzzle using trigonometry.

Geometry Puzzle
What are the dimensions of an inscribed rectangle with the same area as an inscribed equilateral triangle?

Deepwater Horizon Tragedy
How deep was the Deepwater Horizon boring when the disaster happened?

How much money do bloggers make?
Can you earn a living just from blogging?

Refuelling in cold weather
Can you save money by refuelling your car in the morning when the temperature is colder?

Lissajou Curves
Generating pretty pictures using sine waves.
March 2015

Rich Boy Learns Anagrams
Generating and solving anagrams.

Pi, PINs, and Permutations
How many digits of Pi do you need to ensure all possible 10,000 four digit PINs are included?

Simpson's Paradox
Why some statistical results seem to invert when then are combined.

How the manipulation of boundaries can adjust voting outcomes.
January 2015

What is the optimal shape for a bucket?

CES 2015
Notes from my visit to the 2015 Consumer Electronics Show.
December 2014

Deal or No Deal?
Is there an optimal strategy for playing this game?

100 prisoner escape
A classic prison escape puzzle featuring 100 prisoners, 100 boxes and 100 tickets.

Dealer Button Bias
How much bias is there in selecting the position of the dealer by the first person to turn over an ace?

How much does a cloud weigh?
How much does a cloud weigh, or do they float weightless?

Impossible escape?
Can you use math to escape from, what seems like, an impossible prison escape problem based on coins and a chessboard?
November 2014

Shuffling Algorithms
Have you been writing shuffling algorithms incorrectly your entire life?

Gray Codes
What are Gray codes, and why are they so useful?

Giant iPad
If all the iPads in the World were combined into one giant device, what would it look like?

Triangular Trusses
What is the minimum number of crosses braces you need to make a rectangular grid stable?
October 2014

Red/Black Gambling Game
If you draw cards from a shuffled deck, earning $1 for every black card turned over, and losing $1 for every red card, when should you stop?

Langford's Sequences
Arranging pairs of numbers so that the gap between them is distinct.

Exciting soccer games and ballots
If you ultimately win a soccer game, what is the probability you were always winning?

Angle of Repose
Why are volcanoes and sand dunes shaped the way they are?
September 2014

Jello and Lasers
If you shine a laser through a grid of Jello cubes, how many does it pass through?

Optimal Rope Swing
Where should you let go of a rope swing to get the furthest distance into a lake?

Flag of the World
If we merged together all the flags in the World, what would it look like?

Message in a bottle
Send and receive one-time anonymous fortune cookies to random people in the World.

Lowest Discrete Auction Game
Can you guess the lowest distinct number out of a group of people?
August 2014

Countdown Letters Game Solver
A tool for solving the letters round games on Countdown.

Countdown Numbers Game Solver
A tool for solving the numbers round games on Countdown.

Countdown Numbers Game
An analysis of one of the longest running game shows on TV.

Missile Guidance Systems
How do modern missile guidance systems work?
July 2014

Why are cans shaped the way they are?
What is special about cylinders, and why do they have specific aspect ratios?

Why are ice cream cones shaped the way they are?
Using calculus to optimize your ice cream consumption.

Fitting spheres inside cylinders
What is symbol is inscribed on Archimedes' tomb, and why?

Carving Cylinders from Spheres
What is the largest volume cylinder it is possible to carve from a solid sphere? Also, so you know about the napkin ring problem?

Bad Hashing Function
Random trivia about converting words to numbers using the substitution cypher A=1, B=2 ...
June 2014

Optimal Packing
How to efficiently tessellate various numbers of circles into a square.

Coffee Time Challenges
Bite sized problems just hard enough to be tackled over a good cup of coffee.

Sampling and Confidence levels
What confidence levels in statistics mean.
May 2014

DataGenetics Greatest Hits
I've been writing my blog for three and a half years. Here are the top ten most read articles (per year).

Why do I blog?
I've been writing my blog for three and a half years. Why do I do it? How do I do it?

Known as 'Amidakuji' or 'Ghost Leg' - The clever way that Asian nations randomly shuffle outcomes using just pen a paper.

Friday the 13th
The 13th of any month is more likely to fall on a Friday than any other day of the week!

How Radar Works
A simple look at detecting targets in noisy clutter
April 2014

Holographic Replicators
What is the chance of escaping from a pack of angry, laser toting, monsters using a holographic replicator?

Geometric Mean
Calculating geometric means in SQL server without using aggregate functions, and why widescreen TV aspect ratio is 16:9

Minimum Jeopardy
What is the lowest, theoretical, score it is possible to score in a game of Jeopardy?

Compound Interest
How long does it take to double your money, and just what is 'The rule of 72'?

Fuel Consumption
Why we should really be quoting fuel consumption figures as 'gallons per mile' and not 'miles per gallon'.
March 2014

Roller Coasters
Why are the loops on roller coasters never circular?

The Beauty in Mathematics
What is the connection between Moby Dick, accurate clocks, ski-jumps, roller coasters and cog wheels?

Marathon runners and WWII tanks
Estimating the number of runners in a marathon and spying on WWII German tank production.

Bounding Rectangles
The mathematics of repairing bullet holes in a wall using the smallest rectangle of drywall.
February 2014

Drinking Iced Water
Is it possible to lose weight by drinking iced water?

The fallacy of The Gambler's Fallacy
I used to be superstitious, then I heard it was unlucky, so I stopped!

Sir Isaac Newton and Mr Samuel Pepys
A 300 year old probability puzzle!
January 2014

Our Atmosphere
How the density of our atmosphere changes with altitude.

CES 2014
Notes from my visit to the Consumer Electronics Show 2014, in Las Vegas.

Escaping from a monster in dark room
How do you escape from a monster in a dark room who has handcuffed you and given the key to a rat who runs off?
December 2013

Hiding from monsters using Corinthian columns
How to hide from a laser wielding monster (riding on a train) using a Corinthian column.

Mind Reading Magic Symbol Trick
Can your computer read your mind and predict the magic symbol you were thinking about?

Mind Reading Card Trick
Can your computer read your mind and make a card you were thinking about disappear?

Pixel Scalars
What algorithms do video game emulators utilize to scale up the low-res images, used on old computing devices, to modern hi-res standards?

Why do pipes burst the way they do?
Have you noticed that when pipes burst, they almost always burst the same way?

Risk and Uncertainty
The difference between risk and uncertainty.
November 2013

I don't want a smartwatch, I want a dumbwatch!

Visual Cryptography
How to create perfect secret messages that can be decoded using just your eyes.

Monster Soup
How to avoid being turned into monster soup.

QR Codes
How do QR codes work? How much is it possible to distort one and still have it readable?

De Bruijn Sequences
What does DNA sequencing and guessing passwords have in common?
October 2013

How to escape a monster (using calculus)
You are sitting in a rowing boat in the middle of a circular lake. How do you escape from a smart monster on the shore who can run four times faster than you can row?
September 2013

Privacy is dead! Long live Trust!
An honest discussion about what online privacy means in the 21st century.

Average Speeds
Is it quicker to walk backwards and forwards on a travelator or to simply walk there and back by the side?

Saving Windows
How can Microsoft turn around Windows Surface?
August 2013

Dual factor authentication.

How to rotate an image
How to rotate an image, and a need trick to rotate a bitmap an arbitrary amount in a simple paint package.

Customer Service
Why good customer service so important these days.

Linear Regression
How are best-fit regression lines calculated?
July 2013

Credit Card Numbers
How do credit card numbers work? Parity and RAID.

World's Fastest Man
How does Usain Bolt do what he does?

Exact Percentages and Prime Factors
Exact Percentages, Simplifying Fractions, Prime Factors and Greatest Common Divisors.

How much do you spend on coffee
Over a lifetime, with compound interest, it's probably more than you think!
June 2013

TEDx Seattle - Completed!
Photos and my thoughts from the big day.

Bertand's Box
Pulling random silver and gold coins out of treasure chests (and mischievous pixies).

TEDx Seattle
I will be speaking at TEDx Seattle on June 23rd 2013.

Selecting a random secretary
Selecting a random person (fairly) from an unknown number of applicants.

Imposters in Twitter
The sincerest form of flattery? Impersonated accounts on Twitter.

Triple A
Words containing three A's and no other vowels.

Burst Sausages
Why do sausages split down their length when cooked?

Sicherman Dice
Alternative ways to create dice that sum like a pair of regular dice (and how to cheat at craps!)
May 2013

How hungover can you get? Kids blocks and Calculus!

Use all the vowels
Words that can be made using the vowels AEIOU just once.
April 2013

Broken Keyboard
Turn an asteroid into a steroid with a broken keyboard.

Solving Snake
Solving the classic video game

Roman Numerals
A quick look at the lengths of Roman Numerals.

A case for recursion
Solving a classic interview question using recursion.
March 2013

Rock, Paper, Scissors
Novel twist analysis on the classic game.

l33t speak words
Hex words spelled using l33t speak.

Hex words
The value of xDEAD people?

Hilbert Curves
Fractal Space Filling Fun.

Growing Words
Making new words one letter at a time.
February 2013

Inefficient Rulers
Golomb Rulers and Costas Arrays.

No 'L' quiz
Can you solve these puzzles by making new words through the removal of the letter 'L'
January 2013

CES 2013
Notes from my visit to the Consumer Electronics show in Las Vegas.

The return of the atomic typo
Making new words by switching adjacent letters.
December 2012

Wheel of Fortune puzzle solver
Win big by solving puzzles using this useful tool.

Trivial Wheel of Fortune bonus round
How lucky could you get? A list of English words you can make using only the letters: RSTLNE

Are you worth more in dimes, quarters of nickels?
How much are you worth as your weight in coins?

How to mathematically select the best wife
Or best husband, pizza, or secretary ...
November 2012

Default Digital Photo Filenames
Do you rename your digital photos?

Elemental Words
Dictionary words that can be made entirely from elemental symbols.

Fat fingers and atomic typos
How miskeys on a QWERTY keyboard can make other legitimate words.

Discrete Cosine Transformations
How JPGs work, and how to create fun hybrid hidden images.

How to share secrets securely
How do you distribute a password amongst n-people so that not everyone needs to be present to recreate it?
October 2012

Ring, Ring! Where should you stand to answer three phones?
Where is the optimal location to stand to answer three phones to minimize the distance you need to travel?

Analysis of emoticons used on Twitter
What are the most popular emoticons used on Twitter?

Prefixing an S
Making new words by adding an 'S' to the front of existing ones.

Septic Feline
Twenty word puzzles you can solve by adding the letter 'S'

Logic Puzzle - Gunman and colored dots
Can you use logic to save your life and determine the color of a dot painted on your forehead?
September 2012

Rats live on no evil star - Palindromes and mirror words
English words that make different words in reverse.

PIN number analysis
Is your PIN number too predictable? Detailed analysis on PIN number databases.

Round Pegs and Square Holes
Which is a better fit? A round peg in a square hole, or a square peg in a round hole?

Maximum Jeopardy!
What is the highest possible score achievable in a single game of Jeopardy?
August 2012

The eight Queens problem
How to place eight queens on a chess board so that no queen is attacking any other.

`Uncopyrightable` - Distinct letter words
Words that don't contain more than one instance of the same letter.

Parrondo`s Paradox
How two ugly parents (mathematically) can make a beautiful baby

`I had no idea`. Ketchup, rockets, memes and pleated cups
How to maximize the amount of condiment in your cup.
July 2012

Wake up Redmond!
An open letter to Steve Balmer.

Two Eggs problem
Analysis of the classic "dropping two eggs from a building" interview question
June 2012

Intransitive Dice
Intransitive Dice - How to use math to win free drinks from your friends!

Minesweeper First Click: Quality vs. Quantity
Guest Post - Further analysis on Minesweeper Clicking.

Consequences of living on a sphere
The Golden Gate Bridge is wider at the top than the bottom because of the curviture of the Earth.

How long are your shoelaces?
A brief look into the various methods that shoes can be laced and their relative lengths.

Advanced Minesweeper
Where is the best location to click when playing Minesweeper to maximize the chances of a cascade?
May 2012

Counterintuitive Conundrums
A tribute to Martin Gardner
April 2012

Space - It's mindbogglingly big!
Trying to get a handle on just how big the universe is ...
March 2012

Hangman - You've probably been playing it all wrong!
Learn the optimal strategy for playing Hangman.

Benford's Law - Never try to defraud an engineer!
The totally counterintuitive way that the leading digit of natural variables changes.

CQCQ - Mixed up Morse Code
Analysis of what can happen if you send sloppy Morse Code.

Padlock Puzzle
Coding is fun. Using logic and coding to solve a word padlock puzzle.

Analysis of Domain Names
Everything you wanted to know about domain names, and probably things you did not!

Steganography - How to secretly hide messages
Method for secretly hiding covert images inside other images.
January 2012

Analysis of State of the Union Address speeches
Deep dive into the words used in the last 82 Presidential State of the Union Addresses.

What is the probability of getting a Yahtzee?
Mathematical analysis of getting a Yahtzee.

O! Say can you see ...
Data-mining the White House Visitor log files.

Another successful year for facebook
Facebook finished 2011 with 761 million registered accounts.

A geek plays darts
Mathematical analysis of the classic game.
December 2011

Mathematical analysis of algorithms to play Battleship

Ukranian Missile Base
Photo tour of a missile base in the Ukraine.

Mathematical Analysis of Candyland
Crippled Markov-chain and Monte-Carlo simmulations of Candyland.
November 2011

Mathematical Analysis of RISK
Mathematical analysis of the classic board game.

Mathematical Analysis of Chutes and Ladders
Markov-Chains, Monte-Carlo and Chute and Ladders

Deal-a-Day Deluge
A day in the life of a daily deal.

Facebook World-wide accounts 2011
Breakdown of Facebook accounts, by country, for 2011
September 2011

Living Social and Whole Foods
Tracking the Whole Foods offer on Living Social.
August 2011

Facebook around the World
Facebook populations normalised by country population.

Facebook around the World
Facebook populations by gender.
June 2011

Microsoft, you suck!
No Wi-Fi access for Microsoft guests.
May 2011

Price of soda (per gallon)
Comparisson of various liquids, and their price per gallon.

Why is social gaming so popular?
Discoverability, accessibility and camaraderie.
April 2011

What is a body worth?
How much are you worth as elemental components?
March 2011

Natonal Pi day
Can you find a bitmap of Pi in Pi? (I can!)

Facebook shutdown in Egypt
Facebook temporarily shutdown in Egypt in 2011
January 2011

Analysing sales data using just names
Part three of detailed analysis of names and how to use them to analyse sales data (links to preceeding two articles are in the document).

Data Mining using just names
Part two of detailed analysis of names.

What's in a name?
Part one of detailed analysis of names.
December 2010

Sparks and Recursion
Code to generate sparks.

Facebook year end 2011
Facebook user count for 2011.

Spot the connection
What do all these famous scientists and engineers have in common?

Facebook Casual Game Demographics
Gender and age breakdown of some social games.
November 2010

Laptop XOR iPad
How many devices should you travel with?

Facebook Worldwide (Part 2), 2010
Facebook Worldwide (Part 2), 2010.

Facebook Worldwide (Part 1), 2010
Facebook Worldwide (Part 1), 2010.

Smarter Filling
Simple tiling code.

All the single ladies...
Analysis of facebook relationship status.

Digital Shakespeare
Digital Shakespeare (and data cleanliness).

Mixed up Mr. Darcy
How to generate random classics.
October 2010

Chernobyl and Pripyat
Photo tour of Chernobyl and the ghost town of Pripyat.
July 2009

My computer plays better Bejeweled than I do
Getting a computer to play a game.
April 2009

A 'practical' use for Genetic Programming
Painting my portrair using genetic programming.
January 2009

Play better poker in just five minutes
Strategy cards to teach you the relative odds of the starting cards.