If we think about the tree as a design, it's something that makes oxygen, sequesters carbon, fixes nitrogen, distills water, provides a habitat for hundreds of species, accrues solar energy, makes complex sugars and food, creates micro-climates, self-replicates. So, what would it be like to design a building like a tree? What would it be like to design a city like a forest? So what would a building be like if it were photosynthetic? What if it took solar energy and converted it to productive and delightful use?