One day, a smooth rock and a penny were friends. They liked to play together. The smooth rock said, "I like to roll fast." The penny said, "I like to roll too, but I can't roll as fast as you."
One day, they saw a big hill. They wanted to race down the hill. The smooth rock said, "I will win!" The penny said, "I will try my best." They started to roll down the hill.
As they rolled, something unexpected happened. The penny started to roll faster and faster. The smooth rock could not keep up. The smooth rock said, "I quit!" The penny won the race. The smooth rock was sad, but the penny said, "We are still friends. Let's race again another day." The smooth rock was happy again, and they both went home.
