Four eras of inventions in floating isometric diorama grid

2x2 grid, 16:9, popular inventions of 1850, 1940, 1990, 2026:    I(0) = blank matte background.  I(1) = final isometric miniature world of $ THEME, its landmass cut and shaped as silhouette $ SHAPE, floating as a self‑contained diorama. ∂I/∂t = Δ(I, $ THEME, $ SHAPE) with constraints: isometric projection, base‑shape adherence, center‑outward build order, cross‑section side walls, soft global illumination. Integration: t=0.0–0.15: faint isometric base outline in the silhouette $ SHAPE and a light guide grid appear. t=0.15–0.4: the core landmark of $ THEME rises first at the diorama's center; primary structures block in. t=0.4–0.7: surrounding sub‑scenes and terrain populate outward, tiny figures and details accrue, the world fills in. t=0.7–0.9: edges resolve into a clean cross‑section revealing strata beneath the base; outer props finalize the silhouette. t=0.9–1.0: soft shadows and small labels on the key scenes appear, global illumination settles, final polish. Output I(1) as an 8K isometric diorama masterwork.