We are looking at the nave elevation from a vantage point in the triforium of the south transept. The builders have avoided the use of the spacious gallery in the middle level (compare Notre-Dame of Paris and Laon, below), favoring the triforium already used at Chartres and Soissons. At Amiens we get an impression of perfection--how can this be explained? It is partly through the existence of a well-behaved linear grid of horizontals and verticals and the repetition of architectural forms without visible variation down the 7 bays of the nave. In the diagrams below you can see that the overall transverse section is inscribed inside a square and that the triforium sll, where we are standing, is at the half-way level--this explains the absence of converging orthogonals. The main vessel is proportioned around three squares: the span gives the height of the arcade capitals and two more squares reach the high vault.