The paper deals with notions of complexity in art and architecture. On the basis of a recent sculptural work by Richard Serra, Torqued Ellipses (1997), the notion of complexity is investigated in terms of how it situates the viewer, and affects our sense of space and time. Serra's work is analyzed in terms of the artist's working method, the production of the work, and finally the “external relations” which connect it to the viewer and the context. In each of these steps, the notions of complexity and unpredictability are shown to have a formative role. This gives his work a relevance for several fields using working processes as methods. The relations between space and time, object and context, are redefined in Serra's work, which also gives it a more specific importance for architectural theory and practice.