Click the flag and watch the ferris wheel. Press space to turn the ferris wheel's motor on and off. The only issue is that when you hold down space, the carts continue moving. The ferris wheel's movement is based on mathematical calculations. The code is quite simple. Just look in the code and you'll [probably] understand it. I hope the people on that ferris wheel don't have claustrophobia!
All credits belong to me. And yes, I made it so the clouds always move to the right :P