Wrapping presents has a long history and is, so the social anthropologists tell us, a way of “disguising the commodity and adding a layer of authenticity and personal feeling missing from marketplace transactions”. Personally, I use it as a way of camouflaging a disappointing gift for long enough to give me a chance of getting away before the unhappy recipient realises what they’ve got.

And we do love wrapping presents. Each Christmas, we in the UK use enough wrapping paper to cover the whole of the island of Guernsey, which would make a lovely gift. But present wrapping also brings round one of the greatest conundrums in modern engineering. How do you wrap that oddly shaped present?

Hardest of all to wrap are spherical things, thanks to their Gaussian curvature. Flat planes of paper clearly have zero points of curvature – but each time you create a fold in that plane, you add a point and hence get closer to approximating the curvature of the present...