We tend to think of sculpture as a very static art form, something that sits on a pedestal and we move around it. But Calder injected motion into art in a way that no one else ever had. The mobiles are suspended works of art. They are moved simply by a gentle touch of the hand, or by air currents. They come alive to evoke our experience of nature, like petals of a flower or a leaf fluttering in the wind. These constellations of forms are so ingeniously balanced. They take on different forms as the object moves through space, and so the object is really never the same. We can stand in one place and it moves for us. There is something about Calder that sends us back to childhood, sends us back to the sort of wonders of discovery. They are so delicately constructed that your very presence actually impacts the work of art. This wonderful grace in these slow-moving objects has so much to do with his interest in dance, in performance. It is a kind of choreography of movement. There’s big movement as the entire object spins, but then there are subsidiary movements within the object, designed very carefully so that the elements do not touch one another. And the shadows become a sort of secondary work of art. Calder developed the mobile at a time when artists were interested in communicating the fast pace of modern life. I think the mobiles help to slow us down. We understand that they’re turning; they’re behaving; they’re reacting. There is no way to fully experience a mobile without spending time with it. Calder’s works hold our attention, and any time you can step out of time with a great work of art is a gift from that artist.