Mike Batty, Bill Hillier and Stephen Marshall are all presenting at the 2nd Delft Complexity meeting which runs for the next three days at TUDelft. Juval Portugali is the spirit behind these meetings and the edited book from the first conference in 2009 Complexity Theories of Cities Have Come of Age was the result. Here is the programme. I am going to talk about my work on evolving designs or plans using opinion pooling which is a long standing interest of mine in design theory and methods but it has strong complexity implications for complexity as it shows how plans are arrived at from the bottom up. In fact there is a strong focus in the meeting on cognition. There is a very nice paper by Juval defining complexity in cities and click here to read it.