The number pi has fascinated people for over 4000 years. Bilian Proffen is one of those people. He is an interior decorator and owner of an art gallery in Nörten-Hardenberg. His particular interest lies in complex interactions and art in living surroundings. Thus the idea of having the numbers of pi set in stone.

Now pi lies beneath one´s feet – as a sidewalk plaque or in the sandstone foundation of a building.