I think that at that time and practically ever since, the underlying sense of form in my work has been the system of the Universe, or part thereof. F… - Alexander Calder

The two motor driven "mobiles" which I am exhibiting [August, 1933] are from among the more successful of my earliest attempts at plastic objects in motion. The orbits are all circular arcs or circles. The supports have been painted to disappear against a white background to leave nothing but the moving elements, their forms and colors, and their orbits, speeds and accelerations.

Before, the wire studies were subjective, portraits, caricatures, stylized representations of beasts and humans. But these recent things have been viewed from a more objective angle and although their present size is diminutive, I feel that there is no limitation to the scale to which they can be enlarged....

Wherever there is a main issue the elimination of other things which are not essential will make for a stronger result. In the earlier static abstract sculptures I was most interested in space, vectoral quantities, and centers of differing densities.