Moving along in Chapter 1 of Ecclesiastes on Solomon opining on the mundane works of man, Solomon likens us doing the same stuff over and over to nature which also repeats itself endlessly and seemingly frivolous.  

Ecc 1:6  Blowing toward the south, Then turning toward the north, The wind continues swirling along; And on its circular courses the wind returns.

Ecc 1:7  All the rivers flow into the sea, Yet the sea is not full. To the place where the rivers flow, There they flow again.

The wind never stops blowing, it may change directions, across different seasons but it has no end game, just like the ocean, water may fall onto it and rivers and stream flow into it, but again, it’s not as if there is ending to any of it.  

Contextually, these observations of nature tie into the central premise Ecclesiastes; where human works are vain or meaningless.  

We can work, relax, earn, sleep or slumber, but in the end –  we are all headed to the same place, the grave.  

Again, a very bleak outlook, which is only lifted from us, when the veil is is lifted from our eyes, like Paul in Damascus, and that the realization that a life after this one is waiting for us, when we are walking with Christ who died for our sins.