I came across this log lying on the ground with what appears to be notches cut into it. But why?

The bark has been removed, the branches trimmed and it was just lying there. For what purpose?

I’m curious to see if you can figure it out. I’m not sure if these are really clues, but….

1. I saw it at the local swimming hole on the outskirts of Sulzburg, but it has nothing to do with swimming.
2. It has a daily common functional purpose.
3. Normally you would expect something used for this to be metal – I don’t think I have seen wooden one before.
4. It can be used equally by children and adults.
5. These are usually found in schoolyards or adjacent to roadways.

Think you know? Type your guess in the comments section. then come back tomorrow to see if you were correct – I also took a picture of the log being used.