It would be three-dimensional chess with a million billion squares and a million pieces, and with the rules changing ever move. - Clifford D. Simak

They sat for a moment, regarding one another; neither understanding. As if we were two aliens, thought Blaine. With viewpoints that did not come within a million miles of coinciding, and yet they both were men.

Space is an illusion, and time as well. There is no such factor as either time or space. We have been blinded by our own cleverness, blinded by false perceptions of those qualities that we term eternity and infinity. There is another factor that explains it all, and once this universal factor is recognized, everything grows simple. There is no longer any mystery, no longer any wonder, no longer any doubt; for the simplicity of it all lies before us...

What strange circumstances, or what odd combination of many circumstances, must occur, I wondered, to make it possible for a man to step from one world to another.