Glad you like it Mark. One a few analoigies I use to get the points across to my students.

Its amazing though, how many participants stare at my elbows and say it is supporting the pivot box. And I say..."do you see a pivot box on my elbows? They say... my arms, and I say..see any arms resting on my elbows? Now my arms ARE getting tired, and then someone will whisper... "nothing'.

Ta-da!!!! Now class, does anyone see anyhting on my elbows, and they all sigh and say 'No', and then I ask, so what are my elbows supporting? Nothing! And since my elbows represent the rear steer wheels, the rear wheels are not supporting anything either.

Easier said, then written. lol