Syphilis & Dust Particles.
Lyme Disease. Below, Bubonic Plague.
“Let us suppose infinitely flat beings living in a two-dimensional space. They recognize the other flat animals around them, but cannot imagine anything outside their universe, neither above nor below the plane they inhabit. Objects crossing their space are perceived only as flat planes. So, if we stick the tip of a pencil into their universe, they’ll witness a miracle. Unable to conceive of its source, they’ll think it just magically appeared. If they hid a treasure in a two-dimensional box, we could plunge a hand into their world and, being three-dimensional, make off with the treasure, leaving their detectives without a clue.”
“Similarly, if there was a fourth dimension, a being could manifest in our world in some mysterious, puzzling ways, perhaps pulling on our ears, and we’d see nothing more than its fingertips. It could materialize in our world like a genie in a fairy tale. Our tiny flat creatures could only see the outer contour of the peers on their plane. But we, living outside their space, could see their insides. In the same way, a four-dimensional being could see all our organs at once. It could amuse itself by extracting a bone from our skeleton without breaking the skin, though separating it from the flesh would be a challenge.”
“Now let’s consider time as one of the three dimensions. Two-dimensional beings live in the plane of the present, while the past falls away below, and the future falls from above…”