In principle, any abstraction of the object is allowed which has a sufficiently strong creative power behind it.
Max BeckmannI hardly need to abstract things, for each object is unreal enough already, so unreal that I can only make it real by means of painting.
Max BeckmannHeight, width, and depth are the three phenomena which I must transfer into one plane to form the abstract surface of the picture, and thus to protect myself from the infinity of space.
Max Beckmann