Sisyphus rolls a rock up and hill. He gets close to the top, and then inevitably, it escapes his grip, it falls back down. Thus showing the ultimate futility of all human action.
Sisyphus of course does this over and over for eternity. It is a punishment.
Yesterday, many decades after I read that essay it finally dawned on me that there's another interpretation of the myth.
Sisyphus burned a lot of calories getting that rock up the hill. It was hard work. But when he finally got it to the top he just let it go! Why? He loved to watch it roll! It is entertainment!