The trigrams (three bar thingers) represent the elements that make up the world -- fire, earth, water, etc. The wheel represents the confluence of natural order that feeds one another. Kinda like the taijitu/yin-yang symbol, except without the dualist emphasis. And while this is not as obvious as other symbols on the flag, the white background represents the calm and innocent nature of the world at rest. So with this flag, you have a harmonious human world turning round and round, recognizing the influence of natural forces that make up the physical world, situated atop the infinite and inviting spiritual world that is full of potentiality and possibility.
I hope I'm not putting words in the creator's mouth, but the symbolism is so strong that I can't envision any other way of reading it (if you are previously aware of Korean symbols).
That's very interesting. Since I know next to nothing of the Korean Language, history or culture, I was just researching all its previous flags. I found one with all 6 trigrams but I oscillated between the gold/black as just a change of pace from making them all one color. I did this mostly to what pleased my eye. If it matched up to others good opinions then that was just a bonus.