The ornithopter fell out of the sky, in a long slow dive. The wall cloud above them was much thicker now, though it didn’t seem to be moving any faster. The ’thopter tilted, and Alex suddenly noticed a messy puff of filth, way down at ground level. The cloud of dust didn’t seem to be spinning much. Instead, the dust cloud was spewing. It was clumsily yanking up thin dry gouts of ocher-tinted soil and trying to fling them aside.