Spiral The Spiral consists of seven chimes tuned C to B which are individually mounted on chunky timber posts. As the chimes get longer according to their pitch, so do the posts. The elements of the Spiral are arranged in a 1.5m diameter circle with the chimes facing outward. This gives a unique play experience as children can move through the instrument as they play. The post heights range from 2m tall to 1.2m tall.