As you can see on the Five Dollar note. The picture looks like two towers, still intact.
On the Ten Dollar note it looks like the Twin Tower that got hit by the first plane.
Then the Twenty Dollar Note it looks like Twin Towers are on fire.
So what you see is a simple folding of original American money. If you would fold the sides a little bit, the form that you get, is that of a plane. What means that the four notes perfectly represent four planes. Keep in mind "four planes / four notes". Note Also the names of the two plane companies that were involved with the Twin Tower attack. Which are printed on each side of the note, when folded into a plane, then it is on each wing a name.The only letters you have to add, are airlines. You will get America Airlines, and The United Airlines. The two companies involved in the four attacks. Note the upper hole on one tower was United Airlines while the lower hole on the other tower was American Airlines while matching on the Twenty Note.
On The Hundred Dollar note you can clearly see a smoke plume, coming from a pile of debris. By Putting All Four Notes together it makes a animation of the Twin Towers falling.
When you flip over the Twenty Dollar bill you will see the Pentagon Burning!