The work of art represents an idea in the artist's universe. The more the Object is like the idea the stronger the art. A larger work needs great skill and integrity to keep these masses together seamlessly. It is the actual motion of the particles making up the idea, just like the motion of electrons etc. make up matter. Something which is not moving will not be perceived and if there is no motion at all, nothing exists.
Motion creates space and time, making communication possible.
Both the quality and the quantity of the motion is considered. The togetherness or the integrity of the work. How well the parts of the work play together in their action. Also the relative lack of superfluous or missing parts. The amount of creation in the work.