Bottom middle and smallest top.
Manual kit modular marble machine.
The 3d printed marble machine 3 tulio laanen duration.
Note the engraved line on the middle layer defines the area for the gluing top layer.
Modular kit each marble machine consists of a ball lifter and add on module.
I called these the mainboards and replaceable modules shields.
It allows to build the kit in any configuration.
Glue all the layers together shown on the images.