| 434 / | HD | EDUCATION AND DEMONSTRATION |
| 365 | DF | MEANS FOR DEMONSTRATING APPARATUS, PRODUCT, OR SURFACE CONFIGURATION, OR FOR DISPLAYING EDUCATION MATERIAL OR STUDENT'S WORK {37} |
| 408 | DF | .~ Chalkboard or equivalent means having easily erasable surface {14} |
| 413 | | .~.~ Separate elements having erasable surfaces {1} |
| 414 | DF | .~.~.~> Relatively swingable |