Circle Limit IV (Heaven and Hell)

Woodcut printed from two blocks.
 
Circle Limit IV is based on hyperbolic geometry. Escher claimed to have never understood the mathematics behind it, but with the help of H.S.M. Coxeter (a Canadian Professor) he was able to create hyperbolic graphs and ultimately four “Circle Limit” tessellations. Escher loved how cleanly the increasingly tiny figures represented an infinite plane and at the same time created a smooth border. In essence, the work was an infinity captured and walled off! This final Limit woodcut is the most complex of the tessellated figures and is appropriately nicknamed, “Angels and Demons.”
 
The blocks for CLIV are actually 1/3 the size of the final image. Each block is printed three times to create the whole. Therefore, it took six printings (black block and silver block) to print the final work. Close inspection reveals a pinhole in the very center of the image that he used as a registration point and a pencil dash at the border at the nine o'clock position. He added extra black ink to the final image so that his initials and date were not in the image three times. But if you look closely at a real one, you will see a faint hint of the other dates.