As Louis Sullivan says, form follows the function. At the same time, the function follows materials' attributes. Therefore, the designers always have to consider the quolities or intrinsic values of materials.

 After four weeks for metal exploration, he found mild steel sheet which is thin and light is easy to bend and to fold. But after being processed, it gets rigid and stable aspect. Based on this value, he designed folded sheet ateel stool which still keeps lightness.