| 52 / | HD | STATIC STRUCTURES (E.G., BUILDINGS) |
| 561 | DF | LATERALLY RELATED, INDIVIDUALLY ASSEMBLED COURSES {4} |
| 569 | ![]() | .~ Opposed lateral monolithic projections on modules {2} |
| 570 | DF | .~.~> Locking type; i.e., against lateral separation {1} |
| 572 | DF | .~.~> Opposed projections abutting |