ABSTRACT

F A model of the Mo¨bius strip may be made from a long stripof paper, giving it a half-twist and gluing the ends together, as shown in the diagram.

This strip has only one side and one edge. You may verify this by drawing a line down the center of the strip with a pen, moving along the length of the paper and never letting the pen leave the paper surface. Keep going and you will meet the start of your line, which you drew on only one side of the paper. If you examine the strip, you will find there is no other side left unmarked. The paper strip has only one side. You can trace one edge by drawing a line along the edge, and when you reach your starting point, there will be no other edge left to trace.