Why were human beings so fond of using circular shapes? Was this only for practical reasons, or could there have been other reasons too? What kinds of uses have human beings found for the circular shape?                                                                                                                                                                                                                                                  [Page No. 144]

Both practical and deeper reasons play a part. On the practical side, a circle encloses the greatest area for a given boundary length, so a round hut or enclosure gives the most space for the least wall or fencing. Round cross-sections (pots, towers, pillars) spread pressure evenly and are strong, which suits grain silos and water tanks. Above all there is the wheel: the circle is the one shape that rolls at a constant height, making carts, pulleys, potter's wheels and grindstones possible. A circle also has no corners, so it turns smoothly and is easy to draw with just a peg and a length of string.

But the appeal was not only practical. Circles are everywhere in nature the sun, the moon, ripples on water, the cross-section of a stem, the face of a flower so they felt familiar and natural. Their perfect symmetry (the same under any rotation or reflection) made them beautiful and was often felt to stand for wholeness or perfection, which is why circles appear so widely in art, decoration and religious symbols such as mandalas, halos and rangoli.

Uses humans have found for the circle include wheels and gears, pottery, grindstones and millstones, round huts, forts and wells, coins, plates and bowls, clocks and sundials, arches and domes, and decorative and astronomical instruments.