1
XOR
Recently I was called on to explain the ‘XOR’ operator to somebody who vaguely knew of its existence, but didn’t have a good intuition for what it was useful for and how it behaved.
Simon Tatham
Welcome to my web site. I'm Simon Tatham, a software engineer and free-software author in Cambridge, UK.
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Visit chiark.greenend.org.uk/~sgtatham → On Hacker News May 2010 – May 2026
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2
Possibly all the ways to get loop-finding in graphs wrong
In my puzzle collection , there are many games in which you have to connect points together by edges, making a graph, and the puzzle rules say you must avoid making any loop in the graph. Examples are Net , Slant , and some configurations of Bridges (although not the default one). Loopy and Pearl also care about…
3
Two algorithms for randomly generating aperiodic tilings
[Part of a series: Penrose and hats | Spectres | finite-state transducers | more transducers | refining tilings ]
4
A pair of dice which never roll 7 (2004)
Some friends of mine play the board game Settlers Of Catan . In this game, each player rolls two ordinary dice on their turn, and the number which comes up determines what resources people get for the turn. When a seven is rolled, something special happens: no resources are generated, and instead a robber moves on the…