Ha-haa! Ghengis, my knees and back keep telling me that too!
The brain cells don't hurt much yet, though. I haven't used the calculus of complex numbers for a long time. It seemed very important at one time, but I can't remember the last time I ever used it in anger.
Did I say "can't remember"? Oh Dear, perhaps the brain cells are older than I thought eh?
**************************
Through difficulties to the cinema