I thought you should see this one, which has gone viral:
A players ball has ended over a branch, over the hole… whereby the branch prevents the ball from falling into the hole! What should the player do now? Is the ball holed without penalty? With penalty? Or do the player have to replay the stroke? Or…?
The R&A gave us the answer: The ball was holed without penalty – see below.
This is an excellent example of applying Rule 1-4 which says, that when (other) rules have not decided the question in matter, you should do what is fair.
This rule will by the way be almost the same in 2019.