What I didn’t mention in the interest of brevity was that the metric measurements were intended to be arbitrary, so as not to demean or insult other systems of measurement. The meter was supposed to be 1/10,000,000 of the distance from the equator to the north pole, which I guess was arbitrary enough to spare the yard’s feelings;) That evolution you speak of, the inch is approximately the length of the first joint of the adult thumb and the foot the length of the adult foot. Practical of course and no doubt adjusted to render 12 inches to the foot, a very practical number.