> Not to mention they also demonstrated object-oriented programming

Since 2023 we can study the source code of Lisa (see e.g. https://github.com/rochus-keller/lisapascal). Lisa’s system and applications were written mostly in Lisa Pascal (a compiled Pascal descendant) with some 68000 assembly; these compilers and their runtime bear no resemblance to the Smalltalk VM and bytecode system used on the Alto. The object‑oriented language Clascal was later created, as an "object‑oriented variant of Pascal", and used for the Lisa Toolkit; it later evolved into Object Pascal; both are statically compiled Algol‑family languages with Pascal syntax and a Simula‑style object model, not dynamically typed message‑sending systems like Smalltalk. Apple did not copy Smalltalk’s implementation or its language surface form for Lisa nor the Mac; there is barely any resemblance. What Apple mainly took from PARC were GUI interaction ideas (windows, menus, modeless mouse‑driven editing, later the desktop metaphor). While the December 1979 demos convinced Jobs of the direction, the specific knowledge arrived later primarily through the subsequent move of Xerox PARC personnel to Apple.