crab_synthOriginal synthesis by Martin Grant, 26 December 2014 based on work by Tanner Jacobi and Brett Berger. Incremental improvements by Chris Cain and Matthias Merzenich. 18-glider synthesis completed on 29 December 2014. https://conwaylife.com/forums/viewtopic.php?f=2&t=1533&p=15243#p15243 https://conwaylife.com/forums/viewtopic.php?f=2&t=1533&p=15356#p15356 https://www.conwaylife.com/wiki/Crab