Based on Ellis F. Lawrence's vision, many of the university's buildings are planned around several major quadrangles, many of which abut the 13th Avenue pedestrian mall. The university is known for being the site of a pioneering participatory planning experiment known as the Oregon Experiment, which is also the subject of a book of the same name that evolved into the well known book "A Pattern Language" by Christopher Alexander. The project's two major principles are buildings should be designed, in part, by the people who will use them with the help of an "architect facilitator", and construction should occur over many small projects as opposed to a few large ones.