# In stitches over the reef

Over Christmas in 2005 my twin sister Christine and I decided to crochet a coral reef. Since our childhood in Brisbane, coral bleaching events had become increasingly frequent. Scientists were beginning to understand the whitening of our once-vibrant corals was due to warming waters. The sickly state of reefs indicated climate change wasn’t merely a distant danger but an imminent threat to planetary ecosystems. As we crocheted our first corals, we joked to ourselves that, if the Great Barrier Reef died, our reef would be something to remember it by. A decade on, this prospect looms as a ghastly possibility. {%recommended 6413%}

Born from a fusion of science and art, the Crochet Coral Reef project has its roots equally in handicraft, marine science, community art practice, feminism, environmental consciousness raising and mathematics. The forms we craft are woolly incarnations of hyperbolic geometry, an alternative to the usual Euclidean variety. The swooping, curling, crenellated forms of corals, kelps, sponges and nudibranchs are biological manifestations of hyperbolic surfaces, structures ideal for maximising nutrient intake in filter-feeding organisms.

Nature has had a love affair with hyperbolic geometry since at least the Silurian Period, more than 400 million years ago. Mathematicians spent hundreds of years trying to prove it was impossible. Some were nearly driven mad by the discovery, in the early 19th century, of its logical necessity. “Fear it no less than the sensual passions,” wrote the mathematician Wolfgang Bolyai (1775-1856), “because it too may take up all your time and deprive you of your health, peace of mind and happiness in life.”

One way of understanding a hyperbolic surface is as the geometric opposite of a sphere. A flat, or Euclidean, plane has zero curvature. A sphere has positive curvature. A hyperbolic plane has negative curvature; it may thus be understood as a geometric analogue of a negative number.

Since the 19th century mathematicians have known how to describe such forms with equations, but didn’t have a model of one until 1997 when Daina Taimina, a mathematician at Cornell University who had grown up in Latvia learning handicrafts, realised she could crochet it. Using a simple algorithm – “crochet ‘n’ stitches, increase one, repeat ad infinitum” – Taimina crocheted precise models of hyperbolic geometry and demonstrated materially that in hyperbolic space parallel lines diverge while the angles of a triangle sum to less than 180˚.

The Crochet Coral Reef project takes flight from Taimina’s insight. Instead of sticking to her perfect algorithm, we queer the code by deviating from and elaborating on her pattern. Rather than increasing stitches at a regular rate, we vary the frequency, so ruffles may be gently waving or tightly bunched, thereby emulating different types of coral and other reef organisms. By morphing the crochet code – adding protrusions here and fronds there – we have brought into being crocheted coral ‘species’. It is an ongoing experiment in yarn-based evolution. Just as living things are underpinned by a DNA code, our woollen ecology is underpinned by the code of crochet stitches. There is now a crochet ‘tree of life’.{%recommended 6580%}

Let us not forget that handicrafts were also the original ‘digital’ technologies; the cards used to program jacquard looms later became the punch cards of computers. Figuring with our fingers, we are doing a kind of embodied mathematics and enacting a tangible form of computing.

As well as the reefs we make directly, Christine and I work with communities to help them construct local ‘satellite reefs’. To date more than 10,000 people in 40 cities and countries have made such reefs, which have been seen by more than 2 million people at venues including the Andy Warhol Museum (Pittsburgh), Hayward Gallery (London), Science Gallery (Dublin), the Museum of Arts and Design (New York) and the Smithsonian Institution National Museum of Natural History (Washington DC).

Inspired by the wonders of marine organisms, and by the fanciful play of our imaginations, the Crochet Coral Reef is a handicraft cousin to the ever-delighting sea-creature drawings of scientist-artist Ernst Haeckel (1834-1919). Here art and science together pay homage to the liquid laboratory of the sea.