Spirals

spiral /sp^ir(ð)l/ a & adv MI6 [Fr., or med.L spiralis, f. L spira SPIRE n. see -AL.] A adj 1Winding continuously round a fixed point at a steadily increasing or decreasing distance in the same plane. M16. 2Forming a continuous curve which winds like the thread of a screw in a cylindrical or conical manner; helical. M16. b Med Of a fracture: curving round a long bone lengthwise. L19.

Observed in nature, in many flowers, spiders webs, sea shells and in the chambers of the Nautilus. Humans have used them in ornament for centuries - for example, Erechtheum, the Ionic temple of Athena, built approx 400BC, Athens.