A mural painted on the side of the Rich’s Readimix building on Point Reyes-Petaluma Road was covered in gray last Saturday in the protracted debate over the oyster farm. David Briggs

Early this month, half a dozen people stood outside a defunct factory, painting their biggest project yet: a 13-foot by 6.5-foot mural of the now-ubiquitous sign supporting Drakes Bay Oyster Farm.

Sweating in the heat, the group of painters dipped their brushes in blue and white as they transformed a wall at the old Rich’s . . .