NEWPORT BEACH, Calif.—If you take a stroll down Newport Beach’s Balboa Island boardwalk on any given Saturday morning, as you come to Sapphire Street, you’re likely to come upon Chris Crosson, a businessman turned sandcastle guru, knee deep in sand and water building his latest creation. As a child, Crosson grew up on Sapphire, playing along the sandy shores of the man-made atoll, itself made from dredged sand pulled from Newport Harbor back in 1905. Like many other successful entrepreneurs, Crosson’s story started out with a big idea that ended up becoming something he didn’t intend. However, his version may be slightly unusual—it began with dog waste. In 1988, after witnessing one too many people step in dog waste that littered the sidewalks and sand of his beloved neighborhood, he set out to tackle the poop problem by creating a small portable cardboard dispenser with little bags inside that dog …