Don't panic! They are all probably useful!
At the current state of developing the board there are 4 versions on github repository. Each of these versions is based on a different configuration of the board's peripherals. All of the versions are valid.
The evolution of each version can be see using the following steps:
-version 1: simple Board with no mechanics or electronics
-version 2: added fan funnels and tubing for automatic return of the bearing balls using air pressure
-version 3: added mechanical driven spiral to propagate the bearing balls
-version 4: add the slops for moving the bearing balls better.
All versions will be consolidated in a single parametric model, once the rest of the electronics and mechanics are fully developed.