A joint assembly comprising; an engagement block having a plurality of insert receiving faces; each insert receiving face having a slot, and an aperture at a mid-point of said slot; a plurality of inserts each having a core, at least a pair of ribs projecting from said core, a coupling at an insertion end of the core and a mount at a mounting end of the core, and; a coupling pin; wherein said engagement block is arranged to receive the inserts, with said ribs received into the slots and said core received into said aperture, said coupling pin arranged to be inserted into said engagement block and couple with the couplings of said inserts so as to releasably fix the inserts to the engagement block.