A river puzzle in twelve beats

Lantern Relay

Jewel · play

The tide has only one message. Turn the teal river mirrors so it can reach three listening lanterns before it escapes downstream.

Rotate any teal mirror. The first pulse waits for you.

Read the cause: a mirror turns the current clockwise. A pulse may pass a mirror only once; arrange a branching route that touches all three gold lanterns, then send it.