Abstract: Track members of specific configuration are embedded in the edges of flat panel members. Extrusion members of specific configuration are employed to interlock the track members to one another in differing configurations. Each track member defines a cavity and in a first embodiment, two cavities are brought into abutting relation to one another to form a collective cavity into which a first embodiment of the extrusion member slidably fits. When so interlocked, the panels collectively form a wall or other surface. Additional embodiments enable the panels to be disposed at right angles to one another, to form "+" sign shaped intersections, radial arrays, and the like.