Making a marble track is one of the most amazing things I did. The idea was to place a track in a Victorian dollhouse and to combine this with movement sensors.
By using these movement sensors with the track there is more movement than the marble only. I programmed them t turn on a light in another room as soon as the marble passes them.
Making a marble track requires precise working and a knowledge of the materials you are using. And I am not completely proud of this project, but I learned a lot and in the future, I would like to try making one again.