Intro Materials Should Cover:
arena
string helpers
immutable tree model
nil

Examples:
[ ] Metadesk parse checker
[ ] Metadesk reprinter
[ ] Example of helpers: string helpers, linked lists, map type
                        printing errors, cmd line, file iter
[ ] Datadesk-like setup
[ ] Example type metadata
[ ] Example of simple expression parser
[ ] Example of C-like expression parser (with value and type expressions)
[ ] Example(s) of using overrides
[ ] Example memory clearing in long-running program
[ ] Example multi-threaded parsing