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Re: can a wristband be turned insideout?
Posted:
Jun 14, 1996 7:06 PM


In article <4pg92l$gtd$1@mhade.production.compuserve.com>, Mike Kent <70530.1226@CompuServe.COM> wrote: )The original posting asked for the band to be deformed )"continuously and isometrically". I take this to require )a continuous function D: [0,1] x W > W for which D(0,w) = w )for all w in the wristband W, and for which the distance )(along a geodesic) between w1, w2 in W is the same as the )distance between D(r,w1) and D(r,w2) (along a geodesic) in )the image D(r,W). ) )I don't have an answer, of course, but I think this states )the problem a bit more formally. ) ) )mkent@acm.org
So long as you don't add "differentiably", it can be done. So long as the wristband is not too "tall".
It takes folding. A charming little puzzle has a cardboard band colored black on one side, and white on the other. The puzzle is to turn it inside out.
See one of Martin Gardner's puzzle books on this.
Sorry, I forget which one.
Mike   char *p="char *p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
I don't speak for DSC. < They make me say that.



