The Least Useful Guide to Fukuoka

I thought that a bench is something gives you a relaxation.

These benches look to have been designed to give you directions on how you sit: the ideal distance between someone next to you, and the model angle of your sitting position.  

Probably they are designed to prevent someone from sprawling on the bench (, which I personally think OK when the park is not busy). 
  I’m not sure why I have to be taught how to sit by someone I have never met.