Yellow Tower Button Room Light Puzzle

This puzzle sits at map coordinates 3290, 1670, east of the Yellow Tower behind the chairlift station. Two grey buildings face each other on separate cliffs: one holds a room full of buttons, the other a room full of lights, and a yellow cage between them lets the two players shout across. When the puzzle is activated, the player in the light room sees one of the lights shine and walks to the yellow cage to tell the partner which light is active. Describe it by position and shape - left wall, back wall, the curve, right wall, or the wall to the right of the door - and by how the configuration looks. The player in the button room presses the red button that matches the lit light, repeating until the puzzle is complete.