17 November 25

August Ferdinand Möbius was born on 17 November 1790. He was a mathematician whose fame circles around the strange properties of the "Möbius loop," portrayed by my tie and by the paper band I'm holding. It's peculiar because the loop has exactly one side. What look like two sides of paper actually form a single surface; if you draw a line around the loop, your pencil will travel twice the "length" of the loop and you will see that there is no "inside" or "outside." If you work to cut a Mobius loop in half (lengthwise), you get another single loop! The original loop has a single twist, and the new loop (which has two surfaces) has two twists.

The curious features of Möbius surfaces have applications in mechanical engineering, manufacturing, chemistry, entertainment and art. All of my students in Beginning Philosophy and Beginning Ethics had fun (?) making Möbius loops and learning about their properties.