Driftwood is wood that has been washed onto a shore or beach of a sea, lake, or river by the action of winds, tides or waves.
It is a form of marine debris or tide wrack.

Driftwood floats on a river.
Sometimes the river is calm and quiet.
Sometimes the river is wild, turbulent and unpredictable.
A river can be wide, if so, one is not able to see the other shore.
But a river can be narrow and claustrophobic as well.
Driftwood can get stuck between big rocks hidden in the river flow.
It may have scars of past collisions.
A metaphor for our own path of life and our music more specific.

Enjoy.