A man was walking along the sidewalk with his dog on one of those retractable leashes. The man suddenly moved toward the right to drop something in a waste container; dog continued in a straight line, its leash extending across sidewalk; a youth on a skateboard was in a whiz down the pavement toward them. Man, in an instant, raised the leash; youth, in an instant, ducked under the ascending leash; dog plodded steadily on.