Punk and prog aren’t the most natural pairing, but a small number of bands have been finding the connections — among them, Hella, Flying Luttenbachers, and Upsilon Acrux, a San Diego outfit of variable size, whose core members are guitarist Paul Lai and drummer Jesse Appelhans. Their fifth full-length is a work of dazzling complexity, moving at blink speed over pixilated landscapes of fractured sound. In opener “Who’s Running Shit (Son of Destiny’s Child)”, guitar and drums move in linked, but distinct patterns, occasionally joining in unison, but mostly using each other’s forays as jump-off points; during a lyrical middle section, guitar notes turn liquid and less frantic, while the drums surge and splatter and burst explosively underneath. Points for funniest title go to “Touched by God (In Appropriately)”, and the music, too, seems to grin a little, staccato bursts of guitar and synth setting off clash and stutter of drums, everybody exulting in sheer speed and difficulty. The long “Hiking Up Feelgood Mountain (Further Than Ever Before)” takes down the pace. Still, with its eccentric time signature and off-kilter motifs, the cut remains a testament to complicated striving. Consider these compositions as odd-sided polygons, not quite fitting into the square slots assigned to them, a bit alien in their geometrical precision, yet utterly true to their own difficult nature.