Orthogonal sawtooth with expansion factor 11 Population is unbounded but does not tend to infinity. Its graph is a sawtooth function with ever-increasing teeth. More specifically, the population in generation t = 36*11^n - 37 (n>=1), is 7(t+1)/30 + 746, but the population in generation 12*11^n - 51 (n>=1) is only 635 if n is even, 633 if n is odd. This uses a spark from a period 9, speed c/3 orthogonal spaceship, found by David Bell, to turn a LWSS into a loaf, which is then pulled back by pairs of LWSSs. When the loaf is pulled all the way back, it gets deleted and the cycle begins again. (The deletion is caused by interaction with a LWSS and with 3 gliders which would otherwise form a LWSS.) Try putting something in the path of the c/3, far away from the guns. When the beam of LWSSs hits the resulting garbage, it is likely that a loaf will eventually be formed and pulled back. No matter where the loaf starts, when it reaches the guns it will be deleted by one of 3 different reactions. (The block behind the c/3 is used for one of these; it's not needed for the sawtooth pattern itself.) The beam of LWSSs will again be released and may eventually form another loaf. The process may be repeated many times until either the LWSS beam burns through the garbage or the reaction moves upstream and consumes the guns. Dean Hickerson, dean@ucdmath.ucdavis.edu 5/15/92Xref: sawtooth

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