The pilot-owner was practicing takeoffs and landings in his amateur built experimental airplane. Earlier in the day, he had accomplished several successful landings, and then took a short break. After the break, he flew the airplane again, remained in the airport traffic pattern, and completed an uneventful takeoff and full stop landing. He took off again, made a circuit of the traffic pattern, and set up for a second landing. The pilot described the approach as "perfect," and noted that he was "over the threshold with just the right altitude and airspeed." The touchdown was normal, but during the latter portion of the landing rollout the airplane began to veer to the left. The pilot applied right rudder; the airplane turned right, and exited the right side of the paved runway. About 15 feet off the runway, the left landing gear entered a depression associated with a drainage culvert. The left landing gear was displaced aft and up, and the left wing and nose of the airplane struck the ground. The airplane sustained substantial damage to the fuselage and left wing. The pilot did not cite any mechanical problems with the airplane. In his written report on the accident, the pilot noted that pilots must be "really quick" on the rudder and "can't relax until the airplane is back in the hangar" when flying a taildragger.