How has computation changed architecture? Beyond the adoption of cad software in day to day design, much contemporary architecture displays computational aesthetics through the use of wireframe meshes or algorithmic design. At the same time buildings are allegorical bearers of the new control society, figuratively mimicking the structure of the function, as defined in both mathematics and computer science. Through an examination of telephone switching buildings, as well as the work of Morphosis and others, this chapter explores the function by way of its most vivid incarnation, the black box. What results is a kind of black box architecture in constant tension with itself, selectively hiding and revealing its own computational sources.