A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?
In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?
A sundial has the fewest moving parts of any timepiece. Which has the most?
