True. The purpose of a koan is to lead the individual to higher states of being, consciousness, and enlightenment.
How his house changed while he was gone, how some people were not as loyal as he thought they were
The best way according to him is to make a good fence. The poem's final lines says that good fences make good neighbors. That can mean that if you stick your nose in your yard you will have good neighbors. Of course, this is all figuratively and refers to much greater things in life.
