Algodoo

This scene is an example of a hierarchical master keying system.

The coloring of the keys and locks represents their pairing. Color ordering must match, and white is a wild card. This means the all white key is the grand master key, and the all white lock can be opened by any key in the system. For example, the GRW key (from top to bottom) can open the GRR, GRG, and GRB locks underneat it, its own GRW lock, and the GWW and WWW locks above it. The key pairs can be thought of as a family tree, where a key can open a lock if and only if the lock is either a direct ancestor (parent or grandparent) or descendent (child or grandchild) of the key.