peer reviewed ; This article seeks to trace a history of Team X's experimentations on the issue of housing for the great number and more specifically around the theoretical background leading to the question of impermanence and indeterminacy in the architectural process. Through the writings of the Smithsons, Oskar Hansen, or John Voelcker, a theoretical framework will be defined and then put into perspective in a contemporary context. Two case studies will be discussed: Lacaton and Vassal and Elemental. Connections will be made on the issue of indeterminacy and the concepts of “open structure” and “open aesthetics" will be promoted. These concepts presented here offer an alternative for some other possible formal developments around the question of indeterminacy. We will assess whether the pragmatism of these two contemporary architectural offices allow their proposals, beyond responding to specific situations, to claim the status of a reproducible model, such as one imagined during the 1960s.