The slice — why you only ever see a person

We are built to look down the time axis, never across it. From that one viewpoint a worm is invisible: you get a single circular section, moving, and you call it a body.

This is exactly the trick a flat creature suffers with a sphere. Push a ball through a plane and a two-dimensional observer reports a dot that becomes a circle, swells, shrinks and vanishes — and would be right about every measurement and wrong about the thing. The room lets you turn the camera off the time axis. Nothing about the person changes when you do. Only what is visible changes, which is the whole argument: a perspective is not a neutral window, it is a cut.