18th & Walnut is a proposal for a radical new model of affordable housing. The concept creates a hyper-dense tower of units found only at the smallest and largest end of the apartment offering spectrum, including 128 studio apartments and 32 six-bedroom units. It employs realistic capital financing, extremely dense urbanization, and ecological stewardship in a revolutionary new housing prototype. It puts forth the belief that affordable housing is a key element of neighborhoods on the brink urbanization, doubling down on the issues of density, efficient use of space, and active participation in the city. At 898 dwelling units per acre, the project provides an influx of new residents to downtown, supporting the 12 micro-retail spaces at ground-level as well as the larger urban economy.