The manipulation of existing models permitted Eisenman to venture into the labyrinth of arbitrariness, referring neither to an internal, deep structure, nor to an artificial context. The possibility of computer aided design also generated in the American architect a kind of performance anxiety: whereas many of the projects of the 1990s were characterized by a gradual clarification of the formal mechanisms ideated by Eisenman. However despite the shift introduced by information technologies, one might say that Peter Eisenman has always considered the arbitrariness of architecture as an obligatory condition. Deleuze's theories had now become the conceptual pretext shaping his architecture: the basic rational configuration was deformed through the operation of folding and the Deleuzian metaphor became a real construction. In a surrealistic amalgam, Eisenman was able to start from a homage to German Modernism and merge into it his interest in Deleuze.