Entasis of a Pentagonal Helix
Entasis refers to the thickening of the central part of the columns of Green temples. Neither is this exclusively Greek. The helix, which is a spiral, produces the same effect when applied to a geometrical column such as a square, an octagon, or a pentagon like this. The result is an effect of aliveness. As is well known, all nature tends to the helix–from the flow of water, to wind, tropical storms, or the flow of blood.