" Jones the cat was sitting in front of a port. He found the storm exhilarating and had evolved a frenetic game of swatting at the larger particles of dust whenever one struck the port’s exterior. Jones knew he could never actually catch one of the flying motes. He understood the underlying physical laws behind the fact of a solid transparency. That lessened the delight of the game but did not obviate it. Besides, he could pretend that the dark fragments of stone were birds, though he’d never seen a bird. But he instinctively understood that concept, too. "

― Alan Dean Foster , Alien