I have an earlier post here going over it. But this 1 print is 3 separate prints. I first print the Spine, which has alignment groves. Then I remove it from the print surface and print the back. The print will stop after the first layer so I can add in the spine which is held down with magnets. The I resume. This will print the next layer ontop of the Spine, which melts it in and creates a solid connection, no weaker than a normal TPU print. I then remove it and do the same to the cover.