15x15x10cm you do not need a soldering iron.
Build your own marble machine.
See build instructions here.
A marble machine is a creative ball run contraption made from familiar materials designed to send a rolling marble through tubes and funnels across tracks and bumpers and into a catch at the end.
Build your own marble machine and feel it.
Take a sheet of paper and draw out some ideas.
To connect the motor with battery and.
Place the cut out trash parts between the ball track and use it as the strut.
Then glue all the couplers in the proper slots.
Laser cut wood components motor with rudder arm steel balls.
For simplicity the wires are terminated with pins.
Engraved dotes and squares on the strut and holes in the couplers defines which coupler where should be glued.
Sandpaper knife wood glue.
Think about how you can design your own lifters and get your own ball rolling.
If you can get it to the top gravity will do the rest.
Take a look at these awesome videos to get a few great ideas for lifting the balls of your own marble machine.