OCA have received planning permission for this project in London - an extension and alterations to a semi-detached residence in Herne Hill. Rooms, staggered in plan, jostle to reach the sunny rear garden. The part of the design that is the extension pokes out beyond an two storey annex and uses sturdy masonry corners to mark out its territory in the garden. Sturdy corners mean that walls and retaining walls can share the same architectural expression.