Rewrite closures and scoping rules from scratch. Entirely in JavaScript. Using prototypal inheritance, some clever hat-tips from graphics programming, amnesic function bodies, and this one weird global variable.
Slides are up on Speaker Deck.
To convert some regular JavaScript to the closure-less version demoed, go to https://nybblr.github.io/closures/ and drop in some code.
Note that it is extremely limited and won't handle any edge cases (e.g. multiple var declarations per line, function declarations, etc.)