Overview: The Philadelphia project is a mixed use development currently proposed for a very difficult site in Central City Philadelphia. The brief for the project provided most importantly that the building reach the maximum allowable floor area ratio (F.A.R.) while not being assembled with adjoining site. Subject site measuring less than 42feet in width by about 210 feet in depth from street to street, presents physical and therefore economic challenges. Assembly with adjoining projects is precluded by zoning, as no development of any kind facing Chestnut Street may exceed 60 feet in width. As joining either neighbor to the east or west would throw the resulting site into non conformity, this was not an option. Furthermore, since 63 clear feet are needed for a turning radius in a subterranean garage, it became problematic to provide necessary off street automobile storage without the use of a robotic system. Light and ventilation requirements in so narrow a site, where window at either side were not allowed, led to a form appearing to have two buildings when in fact it is one. Solving this problem allowed natural ventilation to provide many air changes rather than energy consuming mechanical methods being used exclusively. View potential, and environmental quality issue in LEED (Leadership in Energy and Environmental Designs) was enhanced by creating a courtyard accessible to both public sidewalks.