Supposed to open a portal.
Spoiler:Follow the path to a wall adorned with three glowing notes. These must be pressed to match the tone heard when you activated the water wheel. From left to right press them in this order: 1,2,1,3 and a portal will appear.
Spoiler:See 3 glowing glyphs on the wall. Press each one to hear the sound it makes.
Remember the tone heard when the waterwheel was activated. Reproduce that sound by pressing the glyphs in correct order.
Press left, middle, left and then right glyphs. A ring of fire opens up a door on the wall.
After stuckness, tried 2 walkthroughs (above).
Don't work at all...... I wonder why !!
