M.C. Escher - Day and Night, 1938 woodcut in black and gray, printed from two blocks
Escher. The paradox of the impossible constructions and geometric motifs in air, exploring architecture in an imaginative game of distorting mirrors
Alternating Rhythm - The the twisting of the shapes in this tessellation along with the rotation of the colors creates an alternating rhythm.
Mariposas by Escher
m c escher | Liberation - M.C. Escher - WikiPaintings.org
Escher art | Tessellations - Everything You Ever Wanted to Know
The Calvert Canvas: Adventures in Middle School Art!: Warm & Cool Portraits with Tessellations