Crochet coral and maths

By Katherine Nightingale 8 November 2013
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A creative way of representing a mathematical principal has led to the creation of some crafty corals.

WHAT DO YOU GET when you combine maths and environmentalism and a bit of crocheting? A coral reef might not be your first response, but once you’ve one, it make completes sense.

Australian sisters Christine and Margaret Wertheim of the Institute for Figuring in California, US, made the first crochet coral reef after realising their crocheted version of mathematical ‘hyperbolic planes’ looked just like coral.


Their Hyperbolic Coral Reef has toured the world since its first appearance in 2007 and ‘satellite’ reefs have sprung up around the world. Now Melbourne – not normally a place associated with corals – is getting in on the act with a reef created by 142 volunteers.

Mathematicians had long struggled to find a way to create physical models of hyperbolic planes, which are the third geometrical representation of space after flat planes and spheres. It wasn’t until 1997 that Latvian mathematician Daima Taimina found she could make durable crochet models.

The easiest way of thinking about a hyperbolic plane, says Tracy Hayllar, coordinator of the Melbourne Reef, is that flat-leaf parsley is a standard, flat ‘euclidian’ plane and curly parsley is a hyperbolic plane. The ruffled, crenellated structures of corals are hyperbolic, as are some types of lettuce and fungi. They have more surface area than flat planes so are a good shape if you filter feed, like corals do.

Starting from a straight line or a circle, crocheting creates hyperbolic structures when regular numbers of additional stitches in each row are added, in the same way that hyperbolic organisms have extra cells or polyps in each ‘row’. It’s not just that crocheted corals look like real corals; they are actually based on the same geometry. The more stitches, the more ruffled the end product.

Hayllar says Melbourne’s reef is unique in creating an “underwater world”, complete with a dummy diver atop a platform and ladder made from timber recovered from Port Phillip Bay.

But not just healthy, vibrant crocheted corals are on display. The exhibition also contains an area of pale corals highlighting coral bleaching and a ‘toxic reef’ crocheted from materials such as plastic bags and audio tape.

Scientists and divers who have visited the reef have praised its realism, says Hayllar. Some of the work is based on photos of real coral, but many more were experiments in stitching techniques.

The aim is to highlight not just the loss of global or Australian reefs, but Victoria’s corals too. Few people know that 80 per cent of Victoria’s marine life is found nowhere else on the planet, says Hayllar, or that a colourful world lies as close to Melbourne as under St Kilda pier.

“How can people be expected to care about and protect an ecosystem that they don’t even know exists?” she asks.

The Melbourne Reef is on display at the Burrinja Gallery in Upwey, Victoria, until 9 January before touring regional Victoria. For more information visit the blog.