#N Gabriel's p138
#O Gabriel Nivasch
#C A small period 138 oscillator, discovered on October 13, 2002
#C www.conwaylife.com/wiki/index.php?title=Gabriel's_p138
x = 21, y = 21, rule = b3/s23
8b3o10b$7bo2bo10b$7bo2bo10b$7b2o12b4$17b3ob$17bo2bo$20bo$3o15b3o$o20b$
o2bo17b$b3o17b4$12b2o7b$10bo2bo7b$10bo2bo7b$10b3o!