We traced the evolution of structure across time, from the vaults and domes of antiquity to the experimental geometries of the industrial age. Domes, we learned, rely on compression to maintain their strength and the Royal Naval College domes in Greenwich served as architectural test runs for the later dome of St Paul’s Cathedral. Trusses, in contrast, work through tension  -  every joint and beam in negotiation with the forces acting upon it. Duncan cited Westminster Hall’s hammerbeam truss as a masterwork of structural design  -  elegant, functional and expressive of material truth. We studied the iron and glass innovation of the Crystal Palace roof and the transformative reinvention of concrete, noting how drying conditions and times are crucial to achieving proper strength. We also covered point loads and uniformly distributed loads, as well as the distinct functions of columns, beams and trusses. Duncan’s enthusiasm for bridge design underscored the idea that structure is not limitation but opportunity  -  a poetic discipline in itself.