Perfect symmetrical balance would actually be in both directions! But that perfect symmetry isn’t often found - not even in Nature. If you cut an orange in half, you’ll have a great example of symmetry in both directions but if you measured or took photographs of the cut orange sections there wouldn’t be any guarantee that the four cut parts would be “perfectly” the same. So when we discuss symmetry we are talking about a very high ideal, not necessarily the way even Nature herself presents to the world.
That’s what makes this study so much fun! We get the concept but then we see that even when taken to the highest power, there are slight variations. Which if you take this reasoning out a few more levels, you see that evolution happens (and probably the reason Darwin got so excited) because there are always a hundred or eventually a thousand/million small variations on the theme that allows for the variety that is so entrancing in human life and equally entrancing about getting the balance right in a composition.
Who knew the order of the Universe could really be what we’re talking about? But it is. Design principles are rooted in human perception that’s so basic all we need to do is step back and recognize it for what it is, and then learn to use the tools.
Isn’t it great?