White plastic wall panels of various lengths and styles which slot into connectors which stack to form columns between the wall units. Panels come in three lengths and are either windows or doors - there are no solid walls. There are also short foundation parts and steps to allow buildings to have a plinth. Thin plastic roof / floor plates sit on top of walls which can be finished by balustrading and capping parts. Further set back storeys can be built on the roof if desired, anchoring them to the lower building by special column caps. Later sets had coloured window glazing.