Editor’s Note: Published in 1957 ... giving them a single half-twist as if they were one strip, and joining their ends as shown in the illustration below. If you're enjoying this article ...

And the solution involves a Mobius strip. A Mobius strip is a very special type of mathematical structure. Unlike a sphere or a cube, it only has one side. You can see how this works just by ...

The four stamps, issued by China Post, each depicts pi the mathematical constant, the Pythagorean theorem, Euler's formula and Mobius strip. [Photo by Jiang Dong/China Daily] They are enthralled ...