Pufferless breeder (Standing breeder) A shotgun sends an 8 spaceship salvo eastward every 360 gens. Call the spaceships, from top to bottom, A, B, C, D, D', C', B', and A'. D and D' are MWSSs; the others are HWSSs. (The shotgun's output is approximately glide symmetric.) Every 360 gens, two guns and a kickback reaction are used to create a northeastward glider in front of A and B. A and B redirect the glider southeastward. Then C' and D' duplicate it, producing 2 SEward gliders and a block. The second glider escapes, the block is deleted by D, and the first glider is turned NEward by A' and B'. It is duplicated by C and D, again producing an escaping glider, a block that gets deleted by the next D', and another NEward glider. The latter interacts with the next A and B in the same way as the original glider did, 596 gens later and 118 units farther east. Thus, in gen t, there are approximately t/360 gliders zigzagging east, each producing 2 more gliders every 596 gens. So the population is growing by about 5 * 2/596 * t/360 = t/21456 cells per generation, and the total population is about t^2/42912. The gliders occupy a nonconvex quadrilateral with vertices at (approximately) (0,0), (t/4,t/4), (59t/298,0), and (t/4,-t/4). Dean Hickerson, dean@ucdmath.ucdavis.edu 10/12/92Xref: breeder

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