According to the pilot, he had just purchased the airplane which was equipped with retractable landing gear. He had hired a flight instructor to deliver the airplane to his home airport and paid the flight instructor to stay an extra day to fly with him, familiarize him with the airplane, and give him a flight review, as the flight instructor had previously given him a flight review in another airplane he had once owned. According to the flight instructor, all had gone well until they came in for the last landing. The flight instructor had noticed that the landing gear was not down, but kept thinking the pilot was going to put it down, and thought the pilot was reaching over to lower the landing gear but it was too late. The airplane contacted the runway with the landing gear retracted and its fuselage was substantially damaged. The pilot reported that there were no preimpact mechanical malfunctions or failures of the airplane that would have precluded normal operation.