The Design Procedure Language (DPL) is a collection of lisp functions that construct and manipulate a hierarchically organized object-oriented data-base. DPL is intended to be a user language. It can actually be used by a human to build projects. DPL may also be used by programs such as PLA generators, routers, and node-extractors. pdf 
I wrote programs that created semiconductor circuits as part of the MIT Industry Affiliates summer school. I also sensed the emersion in confidence that pervaded the AI lab and came to attribute it to wielding abstractions in lisp. I later compared the experience to Smalltalk. The combination convinced me of the utility of object-oriented programming.
I later did a similar design of Picture Model in Tom Almy's equivalent system coded in forth.