Dwaalhaas optical illusion

Rubin's vase (sometimes known as the Rubin face or the figure–ground vase) is a famous set of ambiguous or bi-stable two-dimensional forms developed around 1915 by the Danish psychologist Edgar Rubin.
They were first introduced at large in Rubin's two-volume work, the Danish-language Synsoplevede Figurer ("Visual Figures"), which was very well-received; Rubin included a number of examples, like aMaltese cross figure in black and white, but the one that became the most famous was his vase example, perhaps because the Maltese cross one could also be easily interpreted as a black and white beachball.  bron wikipedia

dit schilderij is geïnspireerd op de "Rubins vaas" een waterpijp of  2 mensen ( gezichten )  die een joint aan het roken zijn  ?