Mahogany with glass lining the outer wall. Add lights to the steps. For second and third floors. I think it'd be nice if the second floor banister bends to give the appearance the staircase extends from the second floor down. Like a vine.
Black & White House / Formwerkz Architects - There are amazing architecture projects around the world. Here you can see every type of project, since buildings, to bridges or even other physical structures. Enjoy and see more at www.homedesignideas.eu