ON A CITY STREET, STOPPED CAR, PUT IT IN PARK AND GOT OUT ENGINE RUNNING.I WALKED BEHIND CAR TO A HOUSE TO GET SOMETHING OFF OF THE PORCH. WHEN I TURNED AROUND THE CAR WAS NO LONGER WHERE I PARKED IT. IT WAS IN THE YARD OF THE HOUSE NEXT DOOR AND HAD CRASHED INTO THE NEIGHBORS SHORT WALL AND PATIO SET. THE CAR WAS RESTING ON A CINDER BLOCK. I WAS ABLE TO PUT IT IN REVERSE AND DRIVE IT OUT OF THE YARD. IT DID DAMAGE TO THE WALL AND THE PATIO SET. THE STREET WHERE I PARKED WAS LEVEL, IT WAS NOT ROLLING WHEN I GOT OUT OF THE CAR. I DIDN'T SEE IT UNTIL IT WAS STOPPED. THIS IS PROBABLY THE FORTH TIME MY CAR HAS NOT STAYED IN PARK. ON TIME I WAS IN THE PROCESS OF GETTING OUT AND IT STARTED ROLLING BACK, I HOPPED BACK IN AND STOPPED IT. THE OTHER TIMES I CAUGHT IT BEFORE I GOT OUT.