Fill a grid so every row, column and both diagonals add to the same magic constant. Generate perfect squares of any order 3–14 with the real historical algorithms (Siamese ladder, 4×4 complement, Strachey's swap), hover to audit the sums, then try to build your own — the lab checks every line.
Magic constant for order 4: 34 = n(n² + 1)/2. Hover or focus a cell to audit its row, column and diagonals.