In 1969, Van den Broek and Bakema produced an initial design for the Tanthof residential neighborhood south of Delft. The plan envisioned a core of high-rise ensembles along and across the provincial road toward Rotterdam. Low-rise buildings were situated around it. The design was criticized and rejected. A broad working group was formed, the Tanthof Working Group, which worked on an alternative plan with new concepts and methods. Among other things, process-oriented planning was chosen instead of thinking in terms of an architectonic final image; a global structural plan was made on the basis of the existing polder structure; and thought was given to ecology and biodiversity, with space for local flowers and plants, gradual transitions between dry and wet and high and low areas, with attention to biomass as the supplier of raw materials. The composition of the Tanthof working group was diverse. Members of the working group included designers from the office of Van den Broek and Bakema, employees of the municipality of Delft and representatives of Delft residents, including Joost Váhl, Anneloes van den Berg, Hiwe Groenewolt, Frans Hooykaas, Peter Lüthi, Jan Stokla and Abe Bonnema.