This 'ninja house' has holes for walls and ladders for stairs

Taking the stairs can sometimes feel like a chore. But that's nothing for this Japanese couple, who navigate their four-story home by ladder.

House T by Hiroyuki Shinozaki Architects - also dubbed the "Ninja House" - has no interior walls, hardly any floor space, and only a few wooden ladders to maneuver between its levels.

Take a look below at the radical design.