"How does art come into being? Out of volumes, motion, spaces carved out within the space, the universe. Out of different masses, tight, heavy, middling-achieved by variations of size or colour. Out of directional line-vectors representing motion, velocity, acceleration, energy etc.-lines which form significant angles and directions, making up one, or several tonalities. Spaces and volumes, created by the slightest opposition to their mass, or penetrated by vectors, traversed by momentum. None of this is fixed. Each element can move, shift, or sway back and forth in a changing relation to each of the other element in this universe". (Calder quoted in: 'Abstraction, Creation Art Figuratif', Editions les Tendences Nouvelles, Paris 1932).