In a dual spiral staircase, each staircase has their own entry and exit independently while touching back to back like the structure of DNA; though they share one single cylinder-shaped space, they never cross to each other. In that staircase, one side receives bright sunlight through a skylight and in the other side it is cool, crisp and dark. It is as if they represent a shape of two conflicting natures coexisting back to back in one personality or society. When you stand on one side, you have the other side on your back/shadow. Although those two sides coexist at the same time, they rather seem to dynamically balance depending on occasions than equally function all the time.