@Ana1234 - There are a few games you can get now that capitalize on the idea. I bought one for my nephew to play on my tablet the other day.
The idea is that you have to set up complicated arrangements of conveyor belts and other objects to get a ball from one side of the screen to the other, over different obstacles for each level.
I've always wanted to set something like this up in real life, but I don't know how I'd go about getting the stuff for it. Are conveyor belts for sale anywhere the average person can get them?