MUD trees

The MUD trees below depict hierarchies of derivation among MUD codebases. Solid lines between boxes indicate code relationships, while dotted lines indicate conceptual relationships. Dotted boxes indicate that the codebase is outside the family depicted.
Note that codebases are different from individual servers, in the same way that a biological family/genus/species is different from a specific bird at a zoo or fossil imprint in a museum. Some of the codebases below are incredibly popular, with many servers based on them; other codebases may only be found on archive sites, making them available but effectively extinct. For a list of specific servers using some of these codebases, see the Chronology of MUDs article.