Abstract: A construction set has a plurality of first planar components, a plurality of first planar joist components, a plurality of second planar components, a plurality of second planar joist components, a plurality of third planar components, a plurality of third planar joist components, a plurality of plank components and a plurality of gable pieces. Each first planar component has a pair of planar sidewall surfaces, first and second end walls parallel to one another, a top surface having a first vertical groove formed therein, and a bottom surface parallel to the top surface, with the bottom surface having a second vertical groove formed therein, and with the first and second vertical grooves having the same vertical axis.