13 down. The final one gave you a bit of a run for your money, but I think there are a couple conclusions about these that are reasonable. First, your intuition is spectacular when it comes to hearing the right chord. You can't force a wrong chord, because your intuition won't let you! Second, contour is such a friend. Try to match the contour you have visualized with the power chords. It will get a little easier that way.