This paper describes the urban design platform Limes, which uses data interaction and data manipulation as design techniques to build systems of responsive infrastructure. The platform is a current research that the authors, tutor and student, are developing at the Royal College of Art. In this paper we illustrate early stage simulations that intend to show the possibilities the platform can offer on the topic of responsive cities via engaged citizens. By employing voxels as information placeholders, we describe a series of simulation models that, on the base of Transport for London data, interact and create response. The platform addresses the necessity to include local information in global networks and proposes methodologies that combine them together in a flexible and adaptive territory of informational exchange, which, for us, is urban space. We, indeed, use the resilient aspect of each territory as core information the voxel uses to interact with its neighbourhood. Nonetheless the platform is drawn upon the aspects of human creativity and interaction with technology to envision design opportunities for the urban environment. How can space react, facilitate and respond to the flux of information between humans and the environment? Through simulations this paper intends to design responsive spaces, in which interactions constitute the network of responsive cities.