Sensei’s library lists several coordinate systems for the standard 19x19 size Go board. The system shown above must rank as one of the more unusual ones. It was inspired by a recent email from fellow games researcher Ryan Hayward , in which…
A rewrite of this blog post with many new insights and updates appeared in Jan 2026 Most people believe 264-1 = 18446744073709551615, or 0xFFFFFFFFFFFFFFFF in hexadecimal, to be the largest number representable in 64 bits. In English, it’s
This post discusses how to solve flip puzzles like Simon Tatham’s “Flip” or David Johnson-Davies’s 16 LEDs puzzle , where each cell in a rectangular grid represents a light that can be either on or off, and the goal is to have all lights tu…
The cryptocurrency space features endless debates about the pros and cons of various possible emission curves. Prime among them is question of whether supply should be capped (finite) or uncapped (infinite). But is this really an essential
Many people equate Proof of Work (PoW) with one particular instance of it. It’s not hard to understand why. The Hashcash PoW is used not only in Bitcoin but in the vast majority of altcoins as well. In Hashcash, miners all compete to look f…
One can throw 36, 40, or 50 plus any triple up to 120, and these numbers are 0, 1, and 2 modulo 3 respectively. In a picture: This seems rather dificult to count until we start to distinguish cases based on final double and minimum of the f…