It’s a little hard to tell if it’s actually connected to the very similar structure immediately to the west, but which has a different address.
It’s impossible to realize that, seen from a different side, it looks like this:
The 1,700-square-foot home was designed and built in 1949 by noted Seattle architect James J. Chiarelli. According to the landmark nomination, the home is considered a “locally significant example of Northwest Modernism that embodies the distinctive characters of its period of construction.”
The other photos, and more information, can be found at this link,which also says:
Designed by PNW icon James Chiarelli as his own home, this is a model of simplistic beauty. Sited for privacy, w/window walls framing views of wooded, magical backyard. Slightly cantilevered from the foundation, seeming to float above the landscape. Abalone flecked terrazzo floors throughout. L-shaped plan allows for master wing surrounded by nature.
Kafia adds that the house last sold in 2012 for $482,000.
Additional information can be found on this .pdf from the city Landmarks Preservation Board.