Twenty-five years is a long time to deliver smiles. Oh, and chills. Step Afrika! celebrates its silver anniversary this year with a massive tour of America, including New York City for an off-Broadway run. In mid-January, the legendary company—the world’s first dedicated to the tradition of stepping—came to Bethesda’s Strathmore. Each dancer’s footwork is mesmerizing as members of the troupe exact the art of synchronicity set to traditional and contemporary beats. The latest show, Step Xplosion, revealed a portion of new work commissioned by Strathmore that honors African American percussive movements like juba and tap.