What could be easier than to send the ball rolling along an arcuate track, like a pendulum? Nothing! If you do not take into account the fact that on the way the ball may have obstacles that will knock it off the correct trajectory. This is not the biggest problem. You just need to guess the ideal launch moment and the whole mechanism will work synchronously. Can you do it? There are many attempts, so do not despair if something does not work out the first time. Pass all the tests and show everything that you are capable of. Good luck!