17 November 19

Today is the birthday of August Ferdinand Möbius (1790-1868), most famous for investigating the properties of "Möbius loops." You can make one yourself from a long strip of paper that you tape into a loop, including a half-twist. The most significant feature of this object is that it has exactly one side, which you can prove by tracing a line around the loop; without lifting your pencil/crayon at all, you will arrive back where you started. And if you then use scissors to cut down that line, expecting to cut the loop in half (lengthwise), you get the surprising result of a single loop that is twice as big. Möbius loops are famous in art, science and fashion design (particularly for knitted or crocheted scarves). My neckwear for today is a Möbius ribbon!