 At this moment, the rightmost \(B\) has traveled past all the \(C\)s, but only half the \(A\)s; since they are of equal size, it has traveled both some distance and half that distance. The putative contradiction is not drawn here however, presumably because it is clear that these contrary distances are relative to the \(C\)s and \(A\)s respectively; there’s generally no contradiction in standing in different relations to different things. Instead, the distances are converted to times by dividing the distances by the speed of the \(B\)s; half the distance at a given speed takes half the time. Then a contradiction threatens because the time between the states is unequivocal, not relative—the process takes some (non-zero) time and half that time. 