This Shadow Chair is a design of Chris Duffy of Duffy London, a British design firm producing furniture, lighting and interior products.
At first glance, this chair seems to defy gravity, by standing upright while only having two front legs.
It is only on closer inspection that you see that the shadow is part of the chair, and made from steel, which is attached to a metal frame built inside the chair: the chair is resting on its own shadow.