Create a contract that allows you to do the following: 1. Buy Shares for $x from person A 2. Immediately share sells of Facebook 3. If the price of facebook

Create a contract that allows you to do the following: 1. Buy Shares for $x from person A 2. Immediately share sells of Facebook 3. If the price of facebook drops below $x, rebuy for $y 4. Transfer new shares to person A The tricky part is #3 on what conditions do you have to rebuy shares when $y > %x.