Calm surface winds are drawn to urban centers, they then rise above the city and descend slowly on the periphery of the developed core.

As trucks and recreational vehicles must use low gear to descend slowly, an additional lane may also be built on the downhill side.

However, the speed was too low, and the aircraft ended up in an inverted (upside-down) superstall, and started to descend slowly.

After sunset the gossamer-winged prototype was to begin gliding without power and then, using its batteries, descending slowly during the dark hours to 5,000ft.

The snail descended slowly, rotating around its longitudinal axis, and deposited eggs until the entire cavity was filled.