Adventurous multi-instrumentalist Sam Rivers flew his freak flag on a regular basis, which means his catalog offers many deep dives into full-blown oddness. The horn-crowded “Nebula” plays out like a frantic pileup of competing motifs, while the live piece “Sunbeams” sees Rivers oscillate between twinkling and jarring runs of piano. And his sax melodies prove especially unmoored on the wide-open “Motivity,” from the aptly titled album Vista.