The architectural firm y+M designed this house in Japan. It's two stories tall and one exterior side is a functional staircase:

To allow sunlight into the house, there are a number of glass slits in-between the steps on the south side.The glass slits not only make them feel liberating but also keep their privacy at the same time.[...]

The outside structure links the garden to the rooftop, and the inside of the house links a private porch/reception/lounge area to the bedrooms. The windows are designed and situated to allow in as much sunlight as possible, whilst retaining privacy.

Link via DVICE | Architects' Website (Google Translate) | Photo: Dezeen