Nice puzzle. Here is my solution: 1. John was among the people who washed Peter’s car. 2. John did a number of things to Peter’s car, including washing it. 3. John washed a number of people’s cars, including Peter’s car. 4. John washed a number of Peter’s things, including Peter’s car. 5. John did a number of things, including washing Peter’s car.

I've edited the sentence, now it works better.

John cleaned his car with water ,which was the same as somebody.

Yes