‘E is een Ezel’ (Donkey)

E is for Escher.  In this wood engraving, E is for Esel, the Dutch work for Donkey.  The donkey pokes his head out of a wall of tessellated 'E's', naturally. 
 
This work was part of an alphabet series created by a group of Dutch artist.  Escher was also tasked with creating the letter M.