"Rhythm can make an artwork seem active."
This statement is incomplete, I think.
http://en.wikipedia.org/wiki/Rhythm
Elements of art
From Wikipedia, the free encyclopedia
The elements of art are a set of techniques which describe ways of presenting artwork. They are combined with the principles of art in the production of art. [1]
The elements of art can include some or all of the following: color, value, line, shape, form, texture, and space.