Place the digits 1-9, once each, into every row, column and irregularly-shaped marked nine-cell region. Cells separated by a black dot contain two digits where one digit is double the other. A magic square is a square of NxN cells in which each row, column and both main diagonals sum to the same total. (In this puzzle digits CAN repeat in a magic square.) The entire 9x9 grid is a magic square. In the centre of the 9x9 magic square is a 7x7 magic square. In the centre of that is a 5x5 magic square. And in the very centre is a 3x3 magic square. The dotted lines clarify the positions of the magic squares.