Richard of Richard's House Painters, enters into a contract with Barry under which he promises to paint Barry's house for which Barry promises to pay $15,000 at the completion of work. Richard mistakenly paints
Steve's house next door.
Steve returns from a business trip and is shocked to see his house painted. Richard asks Steve to pay for the work. Steve refuses and tells him to take a flying leap. Under what legal premise could Richard attempt to recover from Steve?