nothing suffers annihilation, but at dissolution there is a change, and things fall back to the essential element in which they were before. - Vitruvius

The stone in quarries is found to be of different and unlike qualities. In some it is soft... in others it is medium... in still others it is hard as in lava quarries. There are also numerous other kinds: for instance, in Campania, red and black tufas; in Umbria, Picenum, and Venetia, white tufa which can be cut with a toothed saw like wood.

In fact, all kinds of men, and not merely architects, can recognize a good piece of work...

Then, too, the columns at the corners should be made thicker than the others by a fiftieth of their own diameter, because they are sharply outlined by the unobstructed air around them, and seem to the beholder more slender than they are.