Lisp machine
Flavors, an early object-oriented extension to Lisp developed by Howard Cannon at the MIT Artificial Intelligence Laboratory for the Lisp machine and its programming language Lisp Machine Lisp, was the first programming language to include mixins. Symbolics used it for its Lisp machines, and eventually developed it into New Flavors; both the original and new Flavors were message passing OO models. It was hugely influential in the development of the Common Lisp Object System (CLOS).