Abstract: A wall includes first and second shelves defining a space therebetween and each have bottom and top surfaces, the top being planar and smooth between induction and outlet sides. A track assembly on the bottom of the first shelf defines guides parallel with the induction and outlet sides and defining sequential slots. A partition has top and bottom portions telescopically coupled for relative vertical translation between a first position, where pins of the bottom portion anchor within receptacles of the second shelf, and a second position, in which the pins are remote from the receptacles. Rollers coupled to the top portion roll along the guides to translate the partition therealong. Locking members opposite the rollers each slide along a latch structure between a locked position in which a locking pin resides within one of the slots and an unlocked position in which the locking pin is remote from each slot.