Abstract: A toy utilized for the erection of toy buildings of various designs, the device including a rigid, planar board having a uniform array of apertures of a particular shape disposed on one side, and a plurality of elongated pillars having different cross-sectional shapes, each of which will fit within any of said board apertures. The pillars include one or more grooved longitudinal sides which interlockably receive the side edge of one or more panels, the pillars and panels providing for the wall structure of the building. The device includes flanged panels for providing different types of roofs and pegged stairs which allow for regular or spiral staircases. The particular board or planar surface aperture in conjunction with the various shaped cross-sectional pillars in addition to the other structural elements provide great variability in the particular and ultimate design of the structure allowing for greater creativity in the user.