An apparatus includes a front panel that includes a front slot along an edge of the front panel and a back panel fixedly coupled to the front panel. The back panel includes a back slot along an edge of the back panel. The front slot and back slot align. A side panel is configured to fold into a gap between the front panel and the back panel, and a pivot coupling at a corner of the side panel. The pivot coupling is slidably coupled to the front and back slots. The corner of the side panel slidably moves along the front and back slots via the pivot coupling, and the side panel is movable from a stowed position in the gap to an open position to the side of the front and back panels by rotating the side panel and moving the pivot coupling along the front and back slots.