Modular furniture unit for assembly by a wedge

The invention regards a wedge for assembling a furniture unit, a kit of parts for a modular shelving unit, and a modular shelving unit for assembly without tools, wherein the wedge is a T-shaped wedge for assembling a furniture unit, comprising: a rectangular plate, wherein the edges of the plate define a length direction and a width direction, a trapezoid plate, superimposed on the rectangular plate such that a first parallel edge of the trapezoid plate is adjacent to a first width edge of the rectangular plate, and wherein the non-parallel edges are symmetrically tapered along the length direction and in the direction away from the first width edge, and a beam, placed at the first width edge, thereby forming the T-shape, wherein the wedge is configured for frictionally engaging two planes within the furniture unit.