$ ./zellige --seed 0000
Zellige is Moroccan mosaic: glazed terracotta pieces, cut by hand, set edge to edge in plaster. Every pattern is a small motif repeated under a symmetry group. Pick the group, shape the pieces, choose the glaze, and reroll until something looks right.
Start from an edge-to-edge tiling (named by the polygons around each vertex, like 4.8.8). From the midpoint of every edge, two rays leave at the contact angle θ and run until they meet a neighbour's ray. Those crossings carve each tile into a star plus the pieces around every vertex. Hankin described the method in 1925, and it produces the eight-point khatam at 4.8.8.
A rosette repeats around one centre instead of across the plane. Cₙ has n rotations and spins one way. Dₙ adds n mirror lines, which is the usual case for the large central medallions on fountains and riad floors.
Any pattern that repeats in two directions belongs to one of seventeen wallpaper groups. The generator places a random motif in one cell, copies it through the group's rotations, mirrors and glides, then translates the cell across the plane. The labels use crystallographic (IUC) notation.