Three Headed Dog was a version Lucid Puppy Linux (529) had the kernel 2.6.37.6 same as Slacko 531 to support newer hardware. By Playdayz based on 5.2.8.
Original thread: http://www.murga-linux.com/puppy/viewtopic.php?t=70736
Richard Erwin did an update of it and other Lucids
http://www.murga-linux.com/puppy/viewtopic.php?t=90461