I did translation to minimal Scheme implementation of Norvig written in Python (http://www.daniweb.com/software-development/python/threads/359370/norvig-an-even-better-lisp-interpreter-in-python) of the impedance code defined in classic book Lisp by Patric Henry Winston and Berthold Klaus Paul Horn from year 1981 (first computer book I ever bought). Errata: diagram has 10 MOhm when the code listed has 1 MOhm.
I could not get eval to see the omega given as parameter to impedance in l and r functions so I had to do define in caller before invoking the function instead. If anybody knows the way to do it in Scheme, I would happy to hear about it. I do not know Scheme and I am trying to import my 1980's MacLisp studies to learn it a little.