Hacker News
- Impossible Figures Library https://im-possible.info/english/library/index.html 16 comments
- M.C. Escher: More Mathematics Than Meets the Eye http://im-possible.info/english/articles/escher_printgallery/ 8 comments
- Solving missing portion of Escher drawing http://im-possible.info/english/articles/escher_printgallery/ 4 comments