x = 44, y = 37, rule = B3678/S34678
29b4ob4o$26b3o4bo4b3o$24b19o$24b19o$23b21o$23boob3o4bo4b3oboo$29b4ob4o
6$25boo$25bo$20boo3bo3bo$11bo8b8oboo$bboo6b3oboo3bob11o$5o4b9obb13o$3o
bo3b26o$5o4b9obb13o$bboo6b3oboo3bob11o$11bo8b8oboo$20boo3bo3bo$25bo$
25boo6$29b4ob4o$23boob3o4bo4b3oboo$23b21o$24b19o$24b19o$26b3o4bo4b3o$
29b4ob4o!
Sparks from two p20 oscillators turn a rocket into a snail travelling
in the reverse direction.  Other period oscillators could also be used.
David I. Bell, April 1997