Artists who helped each other break free

The Catalan artist Joan Miró and the American artist Alexander Calder were friends for years, having first known each other and each other's developing art in Paris. They kept up their friendship even when separated geographically, visiting each other in Spain or America.

Though Miró was primarily a painter and Calder a sculptor, both broke conventions of their genre - and each explored the other's discipline. In 1946 Miró wrote to Calder: "I was very interested in the reproductions of your sculptures. I have looked at them many times, and they are something completely unexpected. You are taking a path full of great possibilities. Bravo! Sculpture is of enormous interest to me right now. For the last two years, during summer vacation, that is all I have been doing and it's very good for a painter to get away from the old story of canvas and frame every now and again."

Getting "away from the old story" neatly summarizes the way both artists produced free-floating constellations of shapes and forms. In Miró's case, he was challenging the limits of flat surface and perspectival space. In Calder's, he was introducing linearity and literal movement instead of solid mass into sculpture.

Miró and Calder were early fascinated by toys. Calder, using wire and scrap materials, first made his reputation with a "circus" that appealed to fellow artists as well as to people with no art interest. He became increasingly abstract, but his floating, revolving, finely balanced wires holding colored shapes evince a sensibility rooted in the cosmic. Miró's paintings are often more biomorphic and surreal, but no less abstract. Understanding is hardly what either artist was about. Simple response comes closer.