For its seventh annual Global Rhythms festival, the Chicago Human Rhythm Project found international percussive forms in the good old American melting pot. A frequent CHRP guest, Washington, D.C.-based Step Afrika! mines the riches of step dancing—a consummate melting-pot art developed by African-American collegiate fraternities in the first half of the 20th century. One of its sources was the juba tradition, in which slaves used their own bodies as percussive instruments when their drums were confiscated for fear of subversive communication. Over the years steppers have added elements from military drills, gymnastics, and break dancing. Chanting, clapping, stomping, and whooping, steppers are like a cross between cheerleaders and African dancers, but saturated in urban cool. Step Afrika! shares Saturday’s bill with Ensemble Español Spanish Dance Theater, which is performing Dame Libby Komaiko’s sinuous, rousing Bolero along with flamenco and Andalusian folk dance pieces. Step Afrika! returns on Sunday to perform with students from Chicago’s Mayfair Academy of Fine Arts on a bill that also features the Mexican Folkloric Dance Company of Chicago, accompanied by Sones de Mexico.