A popular way of constructing non-regular tessellations is MC Escher's "Triangle Trick" which amends the (3,6) Euclidean tessellation.

Summary:[br][br][list=1][*]Polygon(C,D,3)[/*][*]Midpoint(Segment(E,D))[/*][*]Create a Polyline on segment CD tracing the wings and head of the white fish. Rename the polyline i (if needed).[/*][*]Rotate(i, 60°,C) and rename new object i' (if needed).[br][/*][*]Create a polyline from D to F tracing the left wing of the white fish. Rename it j (if needed).[/*][*]Rotate(j, 180°, F) and rename new object j' (if needed)[br][/*][*]list1={i,i',j,j'}[/*][*]Sequence(Rotate(list1, k*60°, C), k, 0, 6)[br][/*][/list]