Ink and Pencil drawings

Triangular endless staircase, which is depicted on the image below, is not common impossible figure.

Artist's gallery http://www.artlib.ru/index.php?id=11&idp=15&fp=2&uid=9563&idg=0&user_serie=0

The image was found at http://www.artlib.ru/index.php?id=11&idp=15&fp=2&uid=9563&iid=166387&idg=0&user_serie=0