Architecture used to focus mainly on the design of buildings. Nowadays, the spaces between them are also important. Applications such as geocaching make even small real-world spaces easy to locate and access; this transforms once marginal spaces into viable assets. A new variant of this theme, called urban agriculture, converts other kinds of idle and underused resources – manpower, space and land, solid and liquid waste – into cheap, fresh and nutritious food for local populations. Aditya Dev Sood (who trained as an architect) leads a panel on these issues at Doors 8 together with ex-architect Marco Susani, who leads the team developing new service concepts for Motorola, and Usman Haque, who designs haunted spaces which he describes as ‘conversant’.