Here is an example in which the Mobius strip is also physically visible. Namely, the old [eight-track tape](http://en.wikipedia.org/wiki/8-track_tape) system, on which I listened to the Cars and Led Zeppelin as a teenager, has an endless tape with one twist, giving the basic tape-position configuration space the nature of a Mobius strip. (The configuration of the head position keeps track of an additional four positions across the tape.) 