Place two 2 by 2 by 22 inch boards parallel to each other with the inside edges 12 inches apart and the 2 by 2 inch ends flat on a work surface.
Position the two remaining 2 by 2 by 22 inch boards parallel to each other with the inside edges 12 inches apart and the 2 by 2 inch ends flat on the work surface. Space the boards parallel to the other set of boards with the inside edges 8 inches apart. These are the legs of the stool.
Align the 2 by 12 by 16 inch board so that the 12 by 16 inch side rests on top of the upward-facing 2 by 2 inch ends of the legs. This is the seat board. The outside corner edges of the legs should be flush with the outside edges of the seat corners.
Drive two evenly spaced flush trim wood screws through the top of the seat into the ends of each leg using a screw gun.
Insert one 2 by 2 by 8 inch board between each of the legs that are spaced with the inside edges 8 inches apart. Place the boards up 6 inches from the floor. These are the cross supports for the stool. Drive two evenly spaced flush trim wood screws through the legs into the ends of the cross supports at each joint.
Insert one 2 by 2 by 12 inch board between each of the legs that are spaced with the inside edges 12 inches apart. Drive two evenly spaced flush trim wood screws through the legs into the ends of the cross supports at each joint.
Fill the screw holes with wood putty using the edge of a putty knife. Allow the putty to dry and sand the putty flush with the surface of the wood with 120-grit sandpaper.
Apply a wood finish to the kitchen stool. Allow the finish to dry 24 to 48 hours prior to use.