Don't understand the meaning of this sentence

You sit on the swing, spread your arms to your sides, let two people push your arms together, and keep your arms at your sides, so that you will be pushed forward by these two people.

Similarly, if you ask one of the two people to stop pushing you while the other person is still pushing your arm, you will turn around on the swing.

Your two arms are wings, two people are propellers, one propeller is shot down, and you just turn around.