7
4
9
3
8
1
7
4
3
5
4
6
9
5
7
1
2
8
9
3
8
7
1
4
7
9
3
6
4
3
2
1
9
4
5
8
9
"The mind is not a vessel to be filled, but a fire to be kindled." — Plutarch
"The mind is not a vessel to be filled, but a fire to be kindled." — Plutarch
Latin squares, the mathematical structure behind Sudoku, were studied by Leonhard Euler in the 18th century.
Latin squares, the mathematical structure behind Sudoku, were studied by Leonhard Euler in the 18th century.