I was once doing dishes and cooking with the window in the kitchen open. There was a screen in place keep in mind. I left the room for a few minutes and when I did Hopper was curled up on the kitchen rug. When I came back I figured he must have gone downstairs. I kept doing dishes and when I was finished I shut the window. I few minutes later I heard a cat crying in fear from outside. It was Hopper and he was sitting on the top of the camper parked in the driveway. He must have pushed the screen out and then jumped onto the camper.