Lo Shu is one of the oldest and most elegant magic squares. With only the numbers 1 through 9, it forces rows, columns, and diagonals to obey the same sum: 15.
The Lo Shu magic square
Riddle statement
Place the numbers 1 through 9 in a 3\times 3 grid, using each number exactly once, so that every row, every column, and both diagonals add up to 15.
Fill in the grid and check whether you have built a valid magic square.