Most of us have difficulty visualizing the 600-cell "from the outside" in 4-space, or recognizing an outside view of the 600-cell due to our total lack of sensory experience in 4-dimensional spaces, but we should be able to visualize the surface envelope of 600 cells "from the inside" because that volume is a 3-dimensional space that we could actually "walk around in" and explore. In this exercise of building the 600-cell up from cell clusters, we are entirely within a 3-dimensional space, albeit a strangely small, closed curved one, in which we can go a mere ten edge lengths away in a straight line in any direction and return to our starting point.