This Pennsylvania flag design took a very long time to design, and it went through some pretty ugly designs. Anyway, the two stars represent Pennsylvania becoming the 2nd state to enter the Union. The yellow square is is the exact proportions of the Declaration of Independence, which was signed in the state of Pennsylvania. The blue square is in the exact proportions of the Constitution, which was also signed in Pennsylvania. The green represents the main color of Pennsylvania. The blue represents the United States, and so do the five-pointed stars. The five-pointed stars also represent Philadelphia, which used to be the capital city of the United States. Blue and gold are also the state colors of Pennsylvania.
The current Pennsylvania flag is very ugly. Not only does it have black horses on a blue background, but it also has the very complicated Pennsylvania coat-of-arms. What a super-ugly flag! And to think they want to make it uglier!