The young shadows gather.
They have come to listen to the greatest of their seers, the philosopher, eschatologist, metaphysician, mathematician, psycho-historian, stainologist, and, alas as the world knew, serial philanderer, the feigningly meek Umbra, 'U' to everyone on campus.
They sit at his feet, leaving respectful light between them.
"I want to speak of other worlds," Umbra begins. "We know that our universe is complete, whole, self-contained. And we know this because if we begin at one point and travel in a straight line we will eventually, though it may take more time than we have in several life-times, even a number approaching an infinite number of lifetimes, we will return to the same spot. When we look forward in a straight line – and who can look in a crooked one or around corners? – we are looking at the backs of our heads."