The architectural historian Robin Evans wrote an essay about Mies that was to push the climate of opinion other way. In 'Mies van der Rohe's Paradoxical Symmetries', Evans argues that Mies's architecture can only be understood in terms of the way it plays with light. In architectural design drawing, the sheet of paper represents the air into which the ideas of extension and measure will be projected. Before returning to IIT, it may be useful to look briefly at a project by Robert Irwin, 9 spaces, 9 trees, which can be seen as an interesting investigation of the relationships between conceptual structure, drawing and space. The grid of spaces is marked out by a lightweight steel frame supporting panels of blue plastic-coated wire mesh – fencing material. In the case of Mies's architecture, the established form is not a picture; it is a space.