Mima Mounds: Scientists say new laser maps suggest glaciers as the architects of the mysterious humps, but one gopher proponent holds firm. From goofy to erudite, more than three dozen theories have attempted to explain the origins of grassy mounds that dot the prairies of Southwest Washington. The latest twist won't settle the debate, but it casts the mysterious hummocks in a different light. Laser light, that is. Scientists used airborne laser surveys to create topographic maps that reveal new details about the so-called Mima Mounds scattered across lowlands south of Olympia and Tacoma. The technique fires 23,000 pulses a...