Convex and Concave

The left half Convex, the right Concave.  Our eyes fight between mirror symmetry and putting the woman, the man, or the ladder in the appropriate setting. 
 
Escher wrote to Ernst, “Just imagine, I spent more than a whole month, without a break, pondering over that print, because none of the attempts I made ever seemed to turn out simple enough.  The prerequisite for a good print – and by “good” I mean a print that brings a response from a fairly wide public quite incapable of understanding mathematical inversion unless it is set out extremely simply and explicitly – is that no hocus-pocus must be perpetrated, nor must it lack a proper and effortless connection with reality.”
 
This excellent work is available. Please inquire for more info.