abut the completed stud 80 and 82 and a portion of the transverse edge of said rail 18 will abut the tubular sleeve 78 the alignment stud segment 80 of shell 54 projects through a portion of the aperture 120 provided on panel 26 in conjunction and alignment with stud segment 82 of shell 56 the stud segment 80 will hold the panel within slot 58 defined by spaced edges of shell segments 54 and 56 and best seen in fig2 the terminal ends of the rails 16 and 18 will be held within the assembled connectors 22 and 24 through the joint interaction of the alignment pins and sleeves for receiving the pins the abutment studs 80 and 82 and the rail member channels 52 and 48 the alignment stud segments 80 and 82 of the plastic corner segments will fasten the panel 26 within the corner connectors 22 and 24 the rails 16 18 and 20 hold panel 26 within channels 48 and 52 seen in fig2 the ends of rails 16 18 and 20 are held within receptor sockets provided on corner connectors 22 and 24 the rails 16 18 and 20 are prevented from axial movement along their longitudinal axes.