In this chapter, leaving light behind you enter the world of slow-moving mollusks. A snail must get from one corner of a room (dimensions 5 m × 10 m × 15 m) to the diagonally opposite corner in the least time. The snail can walk on any of the four walls but may not walk on the floor or ceiling. What is the path that the snail should take? This free selection includes the Table of Contents, Introduction, and Index.