“What does it all mean?” I asked when I was through.
“Somehow--vaguely--it seems that it ought to mean something.”
“Perhaps,” he said in his kind, sage way, “we really exist in four
dimensions. A part of us and our world that we cannot see and are not
conscious of, projects on into another dimension; just like the front
edges of the books in the bookcase, turned away from us. You know that
the section of a conic cut by the _y_ plane looks different than the
section of the same conic by the _z_ plane? Perhaps what you saw was
our own world and our own selves, intersected by a different set of
coordinates. _Relativity_, as I told you in the beginning.”