| Clue | Source | Date |
|---|---|---|
| Curved structure made from triangles | Universal | 22 Feb 2025 |
| Lightweight structure consisting of interlocking polygons (8,4) | ||
| Structure invented by R Buckminster Fuller (8,4) | ||
| Epcot's Spaceship Earth, architecturally | New York Times | 19 Apr 2019 |
| Epcot's Spaceship Earth, architecturally | ||
| Structure popularized by Buckminster Fuller |