Experimental jazz collides with avant-garde visual pieces in a vibrant exhibit which opened Saturday at the Museum of Contemporary Art Chicago. The Freedom Principle, as the exhibit is called, also includes a series of concerts that will culminate in a 25-hour marathon performance when it closes in November. It combines works by progressive black artists of the 1960s — who were influenced by the creative collaboration and improvisation of experimental music — with pieces by contemporary artists from around the world. Curator Dieter Roelstraete began thinking about how to put on an exhibit exploring Chicago’s rich jazz heritage soon after he moved here from Belgium in 2012. ‘This city is home to some of the greatest jazz musicians the post-war era has ever seen,’ Roelstraete said following a performance by Chicago legend Phil Cohran at a press preview Friday.