#N Four boats_synth
#O 
#C Glider synthesis of four boats (aka. hourglass).
#C https://conwaylife.com/wiki/Four_boats
x = 36, y = 36, rule = B3/S23
33bo$33bobo$33b2o19$25b2o$16b3o6bobo$18bo6bo$17bo2$7b2o22bo$6bobo21b2o
$8bo21bobo5$3o$2bo$bo!