The extensive art collection at Denver International Airport has paid for itself in publicity alone. There's "Mustang," the all-but-fire-breathing stallion by Luis Jiménez that still inspires fear in the timid, and the enigmatic Leo Tanguma murals that have spawned a thousand conspiracy theories. But there are also works with a quieter presence, like Betty Woodman's sumptuous "Balustrade," which many travelers miss because it's on level six of Jeppesen Terminal. Woodman has taken the baluster shape and put her own signature spin on it, creating rows of them out of expressively worked ceramics.