Fortress is sited in order to isolate a single tree and frame it within an unexpected context of a secluded courtyard. In so doing, Fortress activates two environments—one of which it safeguards, the courtyard, and a second of which it houses, the circuitous interior passageway. Materially and tectonically, Fortress is comprised of air and a continuous reflective-mirror surface. Thirty-six identical Mylar panels are seamed to one another to produce a continuous space. Within the context of contemporary discourse of architectural form, Fortress eschews formal complexity and exuberance, and seeks new atmospheric potentials in the most fundamental of forms.