Interlocking shape for use in construction members

A support post rack comprising:

• a primary support post which has a central core supporting at least three pairs of parallel facing surfaces:
• each pair of parallel facing surfaces having a pair of opposed upper facing surfaces which form an entry jaw for receiving an adjoining jaw half from an identically shaped jaw of an adjoining support post;
• wherein each upper facing surface is connected to a respective lower facing surface by a lip;
• a distal tip of each upper facing surface is connected to an adjacent jaw's upper facing surface distal tip by an outer surface;
• wherein the jaw half of an adjoining support post is identical to a corresponding jaw half of the primary support post;
• wherein the jaw half of the adjoining support post will have its lip engaged with the lip of the jaw of the primary support post when the adjoining support post is engaged with the primary support post such that the two jaws interlock together such that the jaw half of the adjoining support post cannot be pulled out of the entry jaw of the primary support post in the direction of the adjoining support post, joining the support surfaces together, the primary and adjoining support posts only being able to be engaged and disengaged from each other by moving the posts relative to each other parallel to the longitudinal axes of the posts.