Molds in shapes of tetris blocks, originally intended for icecubes. I didn't manage to make a non-leaking print, maybe these can be used for flour or so. The source code is organized so you can 'configure' the shapes that you want, by enabling and disabling walls. In Slic3r, choose top layers 0 and 0% infill. I used vertical layers 2 and 3-4 bottom layers. Disclaimer: use at your own risk, our filaments can be toxic for food use! update: I printed it using ABS. After glueing the bottom from the outside with 'ABS juice', it doesn't seem to leak anymore :-)