9. Starting from the center instead of the sides, mark the same grid as above, 3 inches front-to-back and 31/4 inches from side-to-side.

10. Mark each piece with a number, one through four. From front-to-back, the balls will slant downwards. Starting with piece No. 1, which will be the bottom plate of the seat pan, use a hole-cutter bit to drill the following diameters of holes, each centered on the appropriate intersection on the drawn grid. The first row, side-to-side, should be 27/16 inches in diameter. The next row, again side-to-side, should be 2-3/8” in diameter. The following rows should be 25/16, 2-1/4, and 23/16 inches.

11. Piece No. 2 will be the top of the seat pan. From front to back, the rows should be 23/8, 27/16, 2-1/2”, 29/16, and 25/8 inches.

12. Piece No. 3 will be the back of the back cushion. From side-to-side, the balls make a U-shaped contour. This time, each column of holes will be the same diameter, instead of each row. Using a hole-cutter bit, drill a column of holes 23/16 inches in diameter on the outside two rows. On the two rows just inside, the holes should be 25/16 inches. The center column should be 27/16 inches.

14. Sand, stain, and seal the pieces as desired.

15. Drill a total of twelve 1/8-inch diameter holes through the chair frame from top-to-bottom, again taking care to align them as straight as possible. The holes should be centered on the rows of holes in the MDF, the two edge rows and the center row.

16. Drill a matching set of 1/8-inch diameter holes through the pieces of plywood.