Recycling Topology

It’s hard to miss the triangle of three bent arrows that signifies recycling. It appears in newspapers and magazines and on bottles, envelopes, cardboard cartons, and other containers.

The recycling symbol.

Alternative (incorrect?) rendering of the recycling symbol.

Cliff Long made a Möbius band the basis of his wood carving “Bug on a Band.” Photo by David Hampshire, Bowling Green State University

But have you noticed that there are two versions of this ubiquitous symbol? The difference between them lies in the direction of the twist in one of the three chasing arrows that make up the figure.