Eight HDPE panels clip into a dog playpen that stands 32-in tall and reshapes to fit the room: a 76-in rectangle, a 50-in square or a 61-in house layout. Rounded corners and edges cut the risk of scrapes when a puppy bumps a wall. Indoors the pen sits on anti-skid pads, and outdoors 8 stakes grip the lawn. A locking door measuring 18-in by 27-in swings open for entry and latches shut behind. Unlike metal panels the HDPE will not rust, and the waterproof surface rinses clean of odor. Simple connectors assemble the 24.5-lb pen without tools, and extra panels expand it later.