View source for 1RB1RF 1LC1LF 0RE1LD 0LB1LD ---1RC 1RA0RD

{{machine|1RB1RF_1LC1LF_0RE1LD_0LB1LD_---1RC_1RA0RD}}
{{TM|1RB1RF_1LC1LF_0RE1LD_0LB1LD_---1RC_1RA0RD|}} is an unverified [[probviously]] non-halting [[BB(6)]] machine [https://discord.com/channels/960643023006490684/1239205785913790465/1431212803364229170 found by Racheline on 24 October 2025.]

Argument by Racheline:
 this one is probviously non-halting i think
 basically, the tape length has a parity, which changes every time the bouncer hits both ends at the same time. after the parity changes, the iterated bouncer starts from the left end, roughly doubling in size with each iteration, and when it hits the right end, it moves the right end to fix the parity, *except* if it hits both ends at the same time again, in which case it halts.
 assuming that the starting position of the bouncer behaves pseudorandomly and with uniform distribution, the probability of a parity change at a given length should decay linearly with the length, which means the lengths at which the parity changes happen should grow exponentially. for the machine to halt, the length would have to be one of the lengths of the iterated bouncer, and those grow exponentially too. so we need two exponentially growing sequences to intersect, which i think makes it probviously non-halting (unless it gets unlucky and halts early)

[[Category:BB(6)]]