In this puzzle ‘2-digit numbers’ read from left to right or downwards. Box 1 (NW) will contain all the 2-digit square numbers (16, 25, 36, 49, 64, and 81), which may overlap but must be entirely contained within the box. Box 9 (SE) is a clone of box 1, rotated through 180°. In each of boxes 3 (NE), 5 (centre) and 7 (SW), each digit will contribute to at least one 2-digit prime number contained within that box. Box 4 (W) is a magic square, with each row, column, and 3-digit diagonal summing to the same total. In each of box 6 (E) and 8 (S), the two 3-digit diagonals sum to the same number (NB box 6's number may be different from box 8's number).