This is less than half of Alexander Calder’s mammoth mobile in the National Gallery of Art’s East Building. The thing is just breath-taking. Now the architecture of the East Building mostly ticks me off. The layouts of the galleries are often awkward, and finding the entrance to those galleries is about as easy as navigating a MC Esher painting come to life. But the atrium is another story; it is simply an astounding piece of work. One of the reasons why is the kaleidoscope patterns of light and shadows the faceted skylights create. Ever hour and every day the place becomes a whole new piece of art.