Results 3 issues of Guy Langston

With safe-locks the depth counts should be the same. Optimistic locking should add a small number of duplicates. # `30min fp` ![image](https://user-images.githubusercontent.com/3845440/102010054-68742280-3d33-11eb-8d30-53f3f678a607.png) # `5min fp! with a bb:lock:* pool` ![image](https://user-images.githubusercontent.com/3845440/102010103-c6086f00-3d33-11eb-8e58-e7777b144f57.png)...

Just for completeness Features: - Animations - Mouse Player Movement - Mouse Crate Move - Undo/Redo - Save/Restore - Animation Solution - Solution Hints

FEATURE