When I explain 4-dimensional geometry to the layperson, I usually begin with forward, sideways, upward, and, then, inward as the fourth direction needed. It helps a little.
Earlier this month I went a few hours north to explore places I haven’t visited before, which is may way to begin an introspection.
One of the stops was the Portland Arch Nature Preserve, which features one of the rare arches of this state.
To move inward, we begin with the broadest perspective, and then slowly refocus on the essential. Aren’t these rocks something?
What was familiar begins to appear strange.
The clearly structured 3-dimensional world begins to dissolve into abstract patterns of color and light.
Are we getting closer to the core of things when we give up our grounding in a rationalized universe?
And do we merely turn upside down when we walk under the arch, or do we also turn inside out?
To paraphrase Heinrich von Kleist: Crossing under the arch a second time has helped to fall back into the state of rationality.
The Inner Frame 