Simple Cot Size Bunk Bed

Bunk Bed for a small area. 60" overall height, made to fit cot-size mattresses (75" x 30"). Made of only standard dimensional lumber (2x4) and 3/4" plywood. No fasteners in the model -- 2 3/4" lag screws recommended for frame, 1 1/2" lag screws recommended for attaching bed surface (at least every 12" linear).