The Marble Puzzle (a short lesson in physics)

It is fun to dig into history and find out with what kids were playing in the pre-battery age.
The idea of this puzzle is to maneuver the two marbles into their own homes left and right at the end of the slope. However, due to the angles involved, it is impossible to achieve this by just tilting the unit. The only way to solve the puzzle is to apply forces on both marbles in the direction of their homes. Tilting works fine for the first marble. The second one is more difficult. Think of how a centrifuge works...twist it! (don't tell anybody)
If you have larger or smaller marbles, just scale it up or down.
Search Thingiverse for “willemvd” to find more pre-battery age kid stuff.