Abstract: A partition lock for a reticular or grid cell assembly having a first and a second planar member. The partition lock comprises a first slot; a second slot; a tab portion; and a receiving aperture. The first slot is defined at a substantially vertical position in the first planar member. The second slot is defined at a substantially vertical position in the second planar member. Each slot has a first and a second side and a width sufficient to accept the member to be inserted in the slot. The second slot sufficiently cooperates with the first slot to allow the first and the second planar member to align within substantially the same plane when the two pieces are interjoined. The tab portion is positioned on the first member extending from the first side of the first slot to a first notch in the second side of the first slot such that the first tab portion is received in a notch formed in the slot.