Shell Challenge! Rules: DO NOT move or bulldoze external walls or platforms. DO NOT bulldoze existing stairs, you can add railings and more stairs. You can change the fences. You can change the roofs. You can place any windows you want. You can replace the doors. You can build all the internal walls you want. You can decorate however you want. You can build external structures, like a greenhouse, extra pool or gazebo. #shell #shellchallenge #decoration