 Rawsthorne found that all but 235 polyominoes of order 9 tile, and such results have been extended to higher orders by Rhoads (to order 14) and others.Polyominoes tiling the plane have been classified by the symmetries of their tilings and by the number of aspects (orientations) in which the tiles appear in them.The study of which polyominoes can tile the plane has been facilitated using the Conway criterion