If you missed it, Bret Victor also uses this profusely in Up and Down the Ladder of Abstraction (http://worrydream.com/LadderOfAbstraction/). Regardless of his use of Tangle, it's a great guide that definitely merits a thoughtful read.

I missed it the first time. Very cool, thanks for pointing it out.

I think we discussed the original mockup of this here: http://worrydream.com/ScrubbingCalculator/