ded view of the various parts of the second embodiment of this invention using rectangular baseplates; FIGS. 7A and 7B are a perspective view and a detail view of the step of scribing lines at impressed marks and marking the mid-point of the thickness for the second embodiment; FIG. 8 is a perspective detail of a routed groove in one half of a built-up shelf to accept the hex post, and FIG. 9 is a