Upon completion of all Drugit rounds, suggested molecules which had any atoms more than 10 Å from any atom around the starting ligand were first removed. PipelinePilot was then used for automatically filtering out chemically unreasonable molecules among the suggestions made by Drugit players, via simple element counting or property filters (e.g., TPSA, clogP, efflux and permeability predictions, and SMARTS custom filters [see SI for details]).