h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Mathematical knots are joined at both ends, or so I'm told - they make a complete loop in such a way that you can't untangle 'em to get a simple loop with no tangled bits.

My knowledge on the matter runs out at this point, so I'll shut up. If someone else knows anything about 'em, though, it'd make an interesting addition to the article...

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This page has got some elementary info on knots: [Broken link removed by Moderator]

I seem to recall learning something about "Reidemaster moves" (spelling?), all to do with a limited set of moves that could represent all possible knot-tying scenarios.