An Accordion Fold Book w/ Removeable Spine. Note that the first and last pages of the Accordion slip into the pockets of the folded two-piece Covers. Then a folded Spine piece is slipped into the pockets to secure the Accordion that then behaves like a spine bound book. Removing the Spine piece allows the Accordion to be fully expanded.
Note in the two-piece Cover, the outside [black] the tabs are folded along the long edge of the book [head to tail] and the inside [kraft] are folded along the short edge [foredge to spine]. The tabs of the inside cover piece are inserted into the slots of the outside. The Spine piece is the thickness of the Accordion block plus an additional amount on each leg with a turned "out" tab to create a bit of friction.