If you didn't catch the titular pun, Triangle Rhysing is a loose, local collective devoted to pieces for massed guitar—you know, the kind of work done by namesake Rhys Chatham and the more prominent Glenn Branca. Almost three-dozen players will gather for this second convocation, which will bring together members of Lud, Horseback, Beloved Binge, Airstrip and more for a celebration of tone and sustain. Of note, this will be the last local appearance by experimental workforce Shaun Sandor in some time, as he is heading west to Texas. Janel and Anthony open. —Grayson Currin