Try to imagine a 4D hypercube as viewed from the fifth dimension. The shape will be static and unchanging, the hypercube is always a hypercube. Now imagine the shape representing a human being from birth to death as viewed from the fifth dimension. That “long undulating snake” imagery we’ve used really is a gross oversimplification – the complex web of atoms and molecules, water and energy, choices taken and not taken, and all the potential “worldlines” representing a single person is a vastly more complex shape than a simple hypercube. In both cases, that extra dimensional pattern casts a shadow into the third dimension which moves in specific ways: but a rotating hypercube casts a much more predictable and essentially unchanging shadow than the 3D shadow cast by a living and breathing human being!