An evil king locked a wizard in a dungeon with nothing but a chair and a shovel. There is a window in the room, but the wizard can't reach it using the chair. The dungeon is surrounded by a cement parking lot that stretches 100 feet in every direction.
The wizard uses the shovel to dig a 50 feet long tunnel and still manages to escape.
The wizard piled the dirt from the 50 ft long tunnel under the window, climbed up on the chair, broke out the window and escaped.