A simple 3-d model of the chair concept shown below.  The strips on which you would sit would be constructed from laminated maple or cherry wood — probably about 5 or six layers of 1/8” strips with the grain going in two directions.  The spacing in between the strips would be large enough to prevent your butt from getting pinched when the wood flexes disproportionately.  The substructure (ie. the frame) would be made out of steel or aluminum tubes, with cross-bracing to prevent it from tilting to the side.