Get: Look, fiddle with it. Qing: elegant and lonely. Shadow: My own shadow.
To understand the shadow is to dance by yourself and look at your own shadow.
The "person" here refers to being a local official. If you can be happy on earth, why go to heaven? Being a local official outside can also achieve something. Why do you have to go back to the imperial court?
Expressed Su Shi's yearning for freedom.