A simple tray to organize and separate your puzzle pieces while building. Helps it be a little less intimidating on those larger puzzles. The trays are 225 mm square and are 20 mm tall. They are stackable to save space. I experimented with several different infill schemes and to cut down on print time and filament use. In the end, I settled on one bottom layer and two top layers. They end up printing in less than 2 hours each. I've also included a lid that you can put over the top of it if wanted/needed. The picture shows one with just infill (no top or bottom layers), but the Print Profile uses the same scheme as the trays (one solid bottom layer and 2 solid top layers).
Use whatever material you're comfortable with and use whatever magic you like to use for maximum "stickage". The corners have a tendency to want to warp upwards a tad, but even with the little bit of warping I sometimes get, the trays still seem to stack fine.