To an engineer, good enough means perfect. With an artist, there's no such thing as perfect.

1998 (traveled to the San Francisco Museum of Modern Art); Calder: Gravity and Grace Guggenheim Museum Bilbao 2003 (traveled to Reina Sofia Madrid); The Surreal Calder Menil Collection Houston 2005-2006 (traveled to San Francisco Museum of Modern Art; Minneapolis Institute of Arts); Calder Jewelry Norton Museum of Art West Palm Beach 2008 (traveled to Philadelphia Museum of Art; Metropolitan Museum New York; Irish Museum of Modern Art; San Diego Museum of Art; Grand Rapids Art Museum); Alexander Calder: The Paris Years 1926-1933 Whitney Museum of American Art New York 2008 (traveled to the Centre Pompidou Paris; Art Gallery of Ontario Toronto); Calder Palazzo delle Esposizioni Rome 2009–2010; and Alexander Calder: A Balancing Act Seattle Art Museum 2009–2010. The judge recognized the problem at the time noting that Perls’s pronouncement would make Rio Nero unsellable. In 1929 Calder had his first solo show of wire sculpture in Paris at Galerie Billiet.

He also produced numerous wire figures notably for a vast miniature circus.