#N Blocked p4-3
#O Adam P. Goucher
#C A period 4 oscillator.
#C www.conwaylife.com/wiki/Blocked_p4-3
x = 21, y = 9, rule = b3/s23
4bo3bobobo3bo4b$3bobo9bobo3b$3bobo9bobo3b$2obobob7obobob2o$2obo13bob2o
$3bo13bo3b$3bobo4bo4bobo3b$4b2o3bobo3b2o4b$10bo!