Look, coral reefs, made from yarn. Aren’t they beautiful? This is one of a dozen or so troughs of subnauticalia on show at the Hayward Gallery from today.

The ‘hyperbolic crocheted coral reef’ is the creation of the Institute for Figuring, a curiously named sci-art outfit from Los Angeles. They’ve exhibited the reefs in several US cities, and now bring their hyperbolic handicrafts to London.

Why hyperbolic? It’s a curious tale, this. I don’t profess to understand the maths of three-dimensional surfaces, but apparently there are three types of geometry: the good old Euclidian system of planes, angles and parallel lines; spherical geometry; and hyperbolic geometry in which the surface curves away from itself from any given point (kind of the opposite to a sphere where the surface curves in on itself). Or something. Any mathematicians reading this, please correct me.

Such a surface eluded simple physical modelling until 1997, when someone figured out a way to do this, implausibly, through the ancient art of crochet (like knitting, but with a single hooked-needle). Here’s a fuller account of this wonderful yarn, which I don’t quite buy (why not just mold the structures out of wax or something?).

Turns out that nature (not Nature) is an old hand at bypassing Mr Euclid. Corals have grown into hyperbolic structures for millions of years. The new exhibition recreates these glorious geometries from thread, with sparing use of beads, plastic ties and other items of haberdashery. The main display is free to view in the Haywood, but other examples can be found inside the Royal Festival Hall until mid-August. Highly recommended.