the men , in their white powdered wigs and waistcoats of sky blue , red , purple and violet , their butternut , gray , white and tan pants , fitting like ballet tights , their codpieces prominent , as they accepted the soft delicate hands of their partners , bowed , their left leg crossed slightly over their right , their head bowed gracefully , their chins turned just at the precise angle , as if looking up at him through the window of time .