Diagram showing the layout of the roughed-out section and guideline on the entablature now in the Capitoline Museums.
No evidence is available for this source.
The diagram shows the relationship between the roughed-out and finished sections of the architrave of the entablature, and the guideline strip cut into the roughed-out section. The guideline is set 2 cm proud of the finished surface of the architrave and 2 cm down from it. It was intended to act as a reference point for the layout of the fasciae not for their final positioning. The detail at the top left shows how the guideline strip was arranged.