Abstract: A play system for enabling a construction to be built has a base plate, the base plate having a plurality of slots in the main surfaces thereof. A container for a toy or game, in the form of a box having two parts hinged together, can be mounted on the base plate. At least one of the parts of the box has a main wall with an edge portion which can be located in one of the slots in the base plate, whereby said container can form one or more walls for the construction.