There is a book called “Pet Architecture Guide Book” by Japanese architects Yoshiharu Tsukamoto and Momoyo Kaijima (a.k.a. Atelier Bow-Wow).

The term “pet architecture” used by the authors of the book refers to buildings that are built in neglected spaces, such as awkward triangular strips left after blocks being chopped up due to subdivisions and road width expansion.

Billboard Building is a Klein Dytham architecture‘s version of pet architecture, built in Tokyo in 2005.

all images: Klein Dytham architecture