On puzzle 15 we do not understand what it is asking us to do. Am i the only one not understanding it?
As setup, the bit, A, near the bottom of the board will either be pointing to the left or to the right - the setup doesn’t specify which, so you choose before releasing a ball - and, based on that, you need to get the appropriate ball caught in the interceptor.
So, A should start pointing toward the ball that’s going to end up being intercepted.
It’s similar to puzzle 14, but with the interceptor above the key bit, and with colours switched.