My original purpose in designing this chair was to make an outdoor chair that was easy to assemble and comfortable.  First I looked at the curvature of a human spine in a 45 degree angle position to determined the flow/curvature of the chair.  In Rhinoceros 3D (digital 3D modeling software) I adjusted the flow of the chair to support the pressure points when sitting.  Then, to accentuate the curvature, slats were designed from large to small and back to large—for a sense of airiness.  The entire chair was milled on a 3-axis CNC machine. The slats lock into a particular place on the “X” frame of the chair and are held on inverted “U” rails cut on the underside of the slats and held immobile by countersunk brass screws.  The assembly process was easy, especially with an electric drill.  The chair can seat two medium size people but is most comfortable for one.