Frampton tectonics: art of joining , the knot = primary method of joining. Mies van der rohe: legible, clear, simple structures, nothing hidden, almost obsessive. Partition walls only logic clarity of structure suspicious when structure is too obvious: details, i beam carries load, clad with other materials, exterior ornamental i beams, how do we historically understand structure, technology. Use of tools and techniques to solve a practical problem. Anything humans are involved in: new tech always combined with old, old buildings tectonic systems. Lateral thrust: cathedral of amiens 1220-1269. Transfers lateral thrust to ground: marc antoine langrier. Pilaster upright architectural member that is treated as a column and that projects from wall. Proposed neo classicism that came out of nature. Nature is the realm of necessity: jg sufflot. Marries gothic system to post and lintel. Used a machine to determine resistance of stone. Every element has its purpose invisible system of masonry iron inside stone.