Abacus, a square tablet which crowns the capital of the column.
This, as pictured in the text, is the common Gerbert abacus.
The height of the abacus is one seventh of the height of the capital.
The flowers on the four sides are to be made as large as the height of the abacus.
The abacus has a width equivalent to the thickness of the bottom of a column.
The abacus is ...