A set of joists are side-by-side atop pillars. I assumed the wall that runs the middle of the building was fully on the beam on the pillars, but 4/5ths of it is free-floating. Only the edge is on anything, and it's just one of the side-by-side joists. So 100% of the load is on 1/5th of the wall...
VIPs are shaped like thick rectangles (fairly-flat boxes, cuboids), for example 20 mm x 400 x 600 mm. If manufacturing started with a sheet of styrofoam - a thick rectangle - I would not be surprised that the VIP has the same shape. In videos I've seen* of vacuum-packing loose powders, the...