The Doric corner conflict
Triglyphs over every column, triglyphs meeting at the corner, square metopes: the three cannot all be kept. Three ways out.
The rules it illustrates
The Doric corner conflict. A Doric frieze cannot obey all three of its rules at a corner: triglyphs over the column axes, a triglyph turning the corner, and metopes as broad as they are high. One of them must give way.
Contract the corner bays. To end the frieze with a triglyph at the corner and keep every metope square, move the corner column inward: make the last intercolumniation narrower than the others by the amount the corner triglyph is displaced.
Vitruvius’s half-metope. Keep every triglyph centred over a column and every intercolumniation equal, and finish the frieze at the corner with a half-metope half a module wide.
Where it appears in the book
In the styles Ancient Greek.
In the chapters The Doric Order, The Classical World.