#N Achim's p4
#O Achim Flammenkamp
#C Period 4 oscillator found in 1988.
x = 11, y = 9, rule = B3/S23
2b2o3b2o2b$bo2bobo2bob$bob2ob2obob$2o7b2o$2bobobobo2b$2o7b2o$bob2ob2ob
ob$bo2bobo2bob$2b2o3b2o!