A “partition” (score) is a special representational form. It is linked to instructions for action and looks forward rather than backward: to the planning of a forthcoming event. The “open score” goes one step further: it articulates the process of producing new realities and their indeterminacy. In his latest publication, Christopher Dell sketches an “open-ended city score.” The term does not refer to a representation of urban sound texture, nor is the city interpreted in an aestheticizing or musicprogramming sense. Instead, urban processes are rendered visible in a new form, by deploying a musical mode of spatial conception as a filter and perspective. For temporality and the dimension of action are vital components in unveiling the visual structures of phenomena in urban practice.