Mathematical Conversations

In 1772 Euler characterized the surfaces that can be covered with paper, allowing bending but not tretching, cutting or wrinkling. For cloth in place of paper, it would be a different question, as cloth is more flexible, and that was answered by Chebyshev in 1878. In this talk we shall see how a ball can be clothed. The modern developments and unsolved problems on the theme will be discussed, through a blend of theory, applications, and pictures.