blocks by robinhouston

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Parabolic flow

Regex to test for divisibility by 11, in base 9

c763265cb1b90ddf9e72

Plouffe’s prime-generating constant

3×3 troll-square matrices with two-digit entries

Three-digit troll-square matrices

Two-digit troll-square matrices

See https://twitter.com/robinhouston/status/1297221537448198145

Search for English words that have a hex representation as a prime number

697f0701fc2d77444722

Assembler source code from https://www.pouet.net/prod.php?which=85227

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86631a1fbaa992840956

b317a2d0cceb780a56df

0bd2a04521333b0025c2

6ed23df94d0d671d6d52

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Sage code to find left-truncatable primes in bijective numeration

The left-truncatable primes in base 10 bijective numeration

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ee107c3a848e162ba4c2

3ed08648e2e786196cb9

2dc1998deaf9f4d0cb3e

findBasis([a,b,c,d], 4, [a,b,e]) does not enclose e

Circles animated with WebGL

Matt Day’s in-place permutation algorithm using JavaScript generators

Clamp at each tick

Using transition.attr as usual

D3 circle transitions: longhand

Convert spreadsheet column letters (A,B, …, Z, AA, AB, …) to index numbers, and vice versa

(timer) Force layout issue with D3 v4.0.0 alpha.45

Force layout issue with D3 v4.0.0 alpha.45

D3 Custom Bundle

An axis with a date scale

A different Hilbert curve animation

A worm on a Hilbert curve

Hilbert curves

A Perl program using only the characters &+-.:<=>acemnorsuvwxz~ – see http://bumppo.net/lists/fun-with-perl/2001/01/msg00019.html

Testing Safari’s strange treatment of declared global variables

Cubes!

More Moiré

Moiré patterns

All the ways to make $39.75 from coins of denominations 1¢, 5¢, 10¢, 25¢, and $1

https://twitter.com/matlock/status/592308642948489216

Constant flux

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A superpermutation on six symbols of length 872

Test case for Safari fullscreen bug

Interactive maze generator

FitzHugh-Nagomo maze generator

A reaction-diffusion simulation using WebGL

Worms 2

Ammonis worms up close and personal

Ammonis worms

Close-up of the chequered grid

Black and white and red all over

How to make a map of the world with D3

Another method for generating “all RGB” images

A 4096×4096 image containing each RGB value once (h/t allrgb.com). Z-order traversal of RGB cube mapped to z-order traversal of 4096×4096 square.

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A brief explanation of the puzzling tweet https://twitter.com/robinhouston/status/381896698714669056

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Solve a variant of the “Question 2” homework exercise from a previous iteration of the Coursera _Cryptography I_ course, proposed by Brian Meyer: https://class.coursera.org/crypto-008/forum/thread?thread_id=59#post-445

Compute the Bang Bang numbers

A family of equal-area projections

Flow experiment II

Experiments in flow

Double stumbling blocks

Stumbling blocks

Spiral triangles

Double Doyle spiral via Möbius transformation

Doyle spiral explorer

Doyle spiral circle packing

Algorithmic painting

Maze flood fill

Dudeney’s hinged triangle-square

Multiple sliders – Talkie demo

Slider – Talkie demo

Countdown – Talkie demo

Head & Shoulders

Simple color animation

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Test case for throwing an exception in Java and catching it in C++

what happens when I run a script (bug in survey branch of whatdotheyknow-theme)

lvalue subroutine behaviour changes

A patch for pdftk 1.44 that fixes an infinite-loop bug

A Sleep sort implementation for http://visualsort.appspot.com/

Mergesort implementation for http://visualsort.appspot.com/

Signatures over time of http://epetitions.direct.gov.uk/petitions/2159

The number of perfect mazes on a 100×100 grid

A version of the algorithm that permits arbitrary clustering of crossings

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856316

When is an odd prime the sum of two squares?

Number of steps taken when switching from Aldous-Broder to Wilson's algorithm at different points

Make the maze demo from weblog.jamisbuck.org display correctly in IE

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