MINIMAL SUPPORTS REQUIRED FOR MAIN MODEL NOT MY MODEL The joining tiles slide into the back (half each main model) to join them together , the end tiles slide into each end like spacers. simply swap end and joining tiles to lengthen/shorten the assembly. This is a model that I recently needed and had to search everywhere to find, I found it as a post on Facebook that didn't link the original creator. It can be printed with barely any supports (only for the bits at the top and the gap in the base.) Have fun making!