«I cannot help mocking our unwavering certainties.
It is, for example, great fun deliberately to confuse
two and three dimensions, the plane and space, or to
poke fun at gravity. Are you sure that a floor cannot
also be a ceiling? Are you absolutely certain that
you go up when you walk up a staircase?»
— Maurits Cornelis Escher
WALL & CEILING L AMPS