Victor Vasarely1906–1997
Distorted grids
Hungarian-French artist regarded as a founder of Op Art, whose distorted grids appear to bulge out of the canvas.
A flat grid, pushed outward from the middle. The page stays flat and a sphere sits on it anyway.
After Victor Vasarely's distorted grids, 1960s

Vasarely built his Vega paintings from exactly this: a regular lattice displaced by a smooth radial function, with no shading of any kind. Curvature is inferred from how the spacing of a known-regular texture changes across a surface, so widening the grid toward a centre is read as that centre coming forward. The form is entirely in the spacing: every line is the same weight and the same colour.
Behind the mathematics
Distorted grids
Hungarian-French artist regarded as a founder of Op Art, whose distorted grids appear to bulge out of the canvas.
Swelling Op Art surfaces
British painter whose black-and-white Op Art of the 1960s made flat canvases appear to swell, ripple and flicker.