Kites and darts that cover the plane without ever repeating. Five-fold symmetry, golden-ratio edges, and no translational grid.
Roger Penrose, 1974
Start with a sun of ten Robinson triangles and deflate. Thin and thick triangles become kites and darts; edges of length φ never line up into a repeating lattice. Five-fold symmetry is allowed here, unlike a crystal.
tiling
TilesKite and dart. Pair them by matching edges and the plane fills without a repeating grid.