This thesis is an exploration of how small independent residential units added one at a time can offer old buildings and the cities they are in the opportunity to gradually grow and change – in a way that isn’t presented by the typical double-loaded corridor build-out. The first component of this exploration is a modular unit that can be brought into existing buildings and assembled in a flexible layout. This House acts as a ‘Core’ that provides basic shelter, warmth, and a place to sleep and prepare food; the density of this unit allows the surrounding square footage to be used for other activities: kids playing, welding a project, or setting up easels for painting. The second part of this exploration is a pattern-based approach to the interaction of these units within the building: given certain rules that govern arrangement what are some possible spatial outcomes?