Artistic Sand Crabs

‘Crab art’ in an out-of-the-way patch of busy Seminyak Beach, Bali, Indonesia. Photo by the author.

A walk on the beach in many parts of the Old World tropics will reveal strange patterns in the sand- swirls and spirals and abstract shapes made of what look like dark and light colored sand grains. Bend down and look closer. The patterns are actually coll…