Quasicrystals

N plane waves of one wavelength, their directions spread evenly round a half-turn, are added together: crests in gold, troughs in ice-blue. One wave gives stripes, two a square grid, three a hexagonal one, and each of them repeats tile after tile. From four on the pattern never repeats, yet it is not disorder: the spectrum in the corner is still 2N sharp points on a circle. Drag Zoom down and you see the same rosettes turning up everywhere, never quite the same.