Talk:Day & Night

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I made a symmetric variant of life some years earlier than Nathan Thompson's 1997 "day and night" variant.

I found a usenet article from 1992 (see link below) that shows this variant, but I defined this variant already sometime in the 80's.

The rule can be described as 24678/3578, but it is more interesting to observe that both survival and birth happens on the same sums of "live" elements in a 3x3 block, i.e., that the rule can be described as 35789, where the numbes are the sums in a 3x3 block that means birth or survival for the middle cell.

In any case, the link below shows both a period-30 pattern and two spaceships.

http://groups-beta.google.com/group/comp.theory.cell-automata/browse_thread/thread/b043bc8a99c0ea9e/1e5c584f6bbf6dbd?q=torbenm+%2Bsymmetric+%2Blife&_done=%2Fgroups%3Fq%3Dtorbenm+%2Bsymmetric+%2Blife%26hl%3Den%26lr%3D%26safe%3Doff%26btnG%3DGoogle+Search%26&_doneTitle=Back+to+Search&d=&fwc=1

This life variant is used in Scott Draves' "Bomb" program (http://draves.org/bomb/).

Torben Mogensen (torbenm@diku.dk)

[edit] "Rule" or "automaton"?

Are these contradictory? Omphaloscope » talk 21:10, 4 June 2006 (UTC)