My word is Marble.
![](http://blogs.unsw.edu.au/clic/files/2020/01/IMG_96591-300x300.jpg)
Top left is some of my own marbles (toothpaste).
Top right is George Rhoads Rolling ball sculpture (Kinetic art).
Below are screenshots of google searches of marble run, race, marbles, game.
![](http://blogs.unsw.edu.au/clic/files/2020/01/IMG_96531-300x150.jpg)
Marble quarries in the Apuan Alps, Tuscany, Italy. The marble industry has a bad environmental impact on the Apuan Alps. Locals and refugees are reclaiming the mountains to close down quarries and replacing them with an alternative economy, They organised rallies, petitions and flash mobs and as result two quarries were closed down.