Before you worry about those, check out the cool buttons above you.
What a coincidence! The buttons that run the individual puzzles are colored the same and are in the same relative location as the colored lines surrounding the 9 circles.
The different colors (both on the buttons and outside the circles) represent the 4 different puzzles - the 3 you already solved, plus the one that gets you to the ending of the Age. To get a closer look at what's inside of the center building you're above, pull down the yellow lever below the circle diagram to go back down. See if you can come up with an idea of where to put the circles by yourself.
