The next step in sculpture is motion.
The sense of motion in painting and sculpture has long been considered as one of the primary elements of the composition.
My fan mail is enormous. Everyone is under six.
To most people who look at a mobile, it's no more than a series of flat objects that move. To a few, though, it may be poetry.
The universe is real, but you can't see it. You have to imagine it.
That others grasp what I have in mind seems unessential, at least as long as they have something else in theirs.