Nice, two nodes setup works for me. But unable to get working three nodes. I have exactly the same loop setup as on your screenshots and I use listening on "localhost" on three Altirra instances (ports 9001, 9002 and 9003 on the same real machine where the emulators are running). There is no error in Devices. But MIDI Maze shows me only "This is a slave machine" in all three instances. Am I missing something?