Wilco guitarist and jazz veteran Nels Cline brought his quartet to the cozy confines of Milwaukee’s Collectivo Back Room on Wednesday, treating a sold-out crowd to a face-melting and mind-bending array of improvisation and jazz classics, including material from the group’s recent release, Currents, Constellations. Along with Cline, The Nels Cline 4 features guitar virtuoso Julian Lage, drummer Tom Rainey and bassist Jorge Roeder. Stephen Bloch shared some photos from Milwaukee.