There is one distance or diameter through the center. There is only one D. Cir equals two pir or just pid, big D with e's pie-eating smile. If you look at e'm askant you can see how the i's drop out in a furtive way to leave only cr/p.

E wears cr/p as a badge of honor on e's tee. It's how e chooses to identify with the infinite Volume. Pir or pid, both are too circumspect. D quantifies directly, but really E's just two r or r as a diminutive D half step down.

As a minor E didn't fly. Twice promoted now, D is much happier as a major, three quarters of a Volare. E gets to fly three quarter skies with three roots dug deep, deep down twice into the sunken earth, a visceral connection to a Cantare.