Sam Loyd’s 1903 Eighth Book of Tan explores the world of tangrams, the pastime of constructing specified shapes from a given set of seven pieces:
“The seventh and eighth figures represent the mysterious square, built with seven pieces; then with one corner clipped off, and still the same seven pieces employed.”
The book includes no solution. The square on the left is just the regular “block” formation above. But if anyone has discovered how Loyd produced a “clipped” square using the same seven pieces, I haven’t been able to find it.