Thesaurus Term/Concept: TETRAHEDRON
| Identifier | 123565 |
|---|---|
| Class | DEFENCE OF BRITAIN |
| Status | Preferred |
| Index? | Yes |
| Scope Note | Triangular concrete pyramids with 6 feet long sides and 5 feet high, intended to impede enemy movement in the event of invasion. Thought to be confined geogaphically to Southern Command. |