If C/d was not pi in curved space, assuming we say it is pi', then pi' =/= pi and the infinite series of pi, like the slow convergent one
4(-1)^n/(2n+1)from n=0 -> infinity, would be incorrect in measuring the circle stuff. also, it would mean that e^(pi*i) is -1, but e^(pi'*i) is also -1 on the...