A Tiling is which all tiles are congruent.
See also Anisohedral Tiling, Isohedral Tiling
References
Berglund, J. ``Is There a -Anisohedral Tile for ?'' Amer. Math. Monthly 100, 585-588, 1993.
Grünbaum, B. and Shephard, G. C. ``The 81 Types of Isohedral Tilings of the Plane.'' Math. Proc. Cambridge
Philos. Soc. 82, 177-196, 1977.