Two regular drawings overlap. Their slight mismatch creates broad bands that belong to neither layer. Drag the second layer, or turn it a fraction, and the apparent pattern changes.
Geometric moiré · superposed periodic patterns
These are actual superimposed lines, not a painted interference texture. Rings respond strongly to displacement; parallel and hexagonal lattices respond to rotation and pitch mismatch. Very dense settings can also interact with the screen's pixel grid; the SVG retains the original lines.
gridwave