In topology, a branch of mathematics, the trefoil knot is the simplest example of a nontrivial knot:

This is Kevin Hutson’s design, well CP really, that I sort of just nutted out after mis-folding it 4 times and uttering some bad words (sorry Mum). The observant amongst you will notice that it starts and finishes at the same point – like a mobiius strip on acid.

I like this a lot, it turns on itself at every corner beginning where it starts – a nifty bit of topology.

Folded from a recycled 5×40 grid, I collapsed it wrong so many times I was beginning to wonder if it would just fall apart from paper fatigue. I like this 90 degree turn trick, must remember it.