Difference between revisions of "OCA:Day & Night"
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'''Day and Night''' is a fanciful variant of '''Conway's Life''' which has at least two inspirations from popular culture. The Life universe, a two dimensional square grid whose binary cells are referred to as 'live' or 'dead' (or ' | '''Day and Night''' is a fanciful variant of '''Conway's Life''' which has at least two inspirations from popular culture. The Life universe, a two dimensional square grid whose binary cells are referred to as 'live' or 'dead' (or 'unoccupied'), or even zeroes and ones, quickly evolves from random initial conditions into a sparsely populated state. Binary automata are associated with complementary automata wherein zeroes and ones are interchanged; some are symmetric with respect to this exchange. Watching Life evolving quickly reminded observers of two similar situations: | ||
: A well known 1938 woodcut by Maurits Escher, actually entitled ''Day and Night'', featured a flock of black birds flying against a background of similarly flying white birds - mirror images of each other. | : A well known 1938 woodcut by Maurits Escher, actually entitled ''Day and Night'', featured a flock of black birds flying against a background of similarly flying white birds - mirror images of each other. | ||
Revision as of 09:07, 22 February 2010
Day and Night is a fanciful variant of Conway's Life which has at least two inspirations from popular culture. The Life universe, a two dimensional square grid whose binary cells are referred to as 'live' or 'dead' (or 'unoccupied'), or even zeroes and ones, quickly evolves from random initial conditions into a sparsely populated state. Binary automata are associated with complementary automata wherein zeroes and ones are interchanged; some are symmetric with respect to this exchange. Watching Life evolving quickly reminded observers of two similar situations:
- A well known 1938 woodcut by Maurits Escher, actually entitled Day and Night, featured a flock of black birds flying against a background of similarly flying white birds - mirror images of each other.
- The symmetry between electrons and the eventually discovered positrons in P. A. M. Dirac's relativistic quantum mechanics.
It was therefore a temptation to adjust the rules of Life to invoke such a symmetry. The 180 degree rotational symmetry of the return map of such a rule places an unstable fixed point at density 1/2, resulting in a characteristic dynamics at boundaries where day meets night. Normal Life evolution or its complement is expected to occur elsewhere.
The most direct adaptation seems to be B3678/S34678, attributed to Nathan Thompson as of April 1997 and discussed in detail by David Bell via the Internet in November of that year.
External links
- David I. Bell (1997). "Day & Night - An Interesting Variant of Life". See also Bell's Day & Night pattern archive.
- Pete Carlton. "Pete's Game of Life Page: B3678 S34678".