Sounds like a dream and a nightmare wrapped in a magneto‑elastic joke. The problem is that any reversible shape change requires the material to keep its bonds intact while shifting lattices, and that only works if the magnetic field energy exceeds the lattice strain energy without blowing the crystal apart. So you end up with a thin, highly specialized alloy that’s stable only under precise field strengths and temperatures. In practice, it’s a constant battle against brittleness, fatigue, and the fact that real buildings need to bear loads, not just bend a few millimeters under a magnet. Theoretical curiosity, yes, but engineering reality keeps it in the lab for now.