#N Fore and back
#O Achim Flammenkamp
#C A period 2 oscillator found in July 1994.
#C www.conwaylife.com/wiki/index.php?title=Fore_and_back
x = 7, y = 7, rule = B3/S23
2ob2o2b$2obobob$6bo$3ob3o$o6b$bobob2o$2b2ob2o!