Kjartan shows how this magic square can produce the target number in at least 24 different ways. These include the 4 horizontal and 4 vertical lines, the two diagonals and the four corners.
 Any "target" number can be chosen for the square, but it's best between 20 and 50.
 The numbers in grey squares remain the same.
 The numbers in yellow squares are dependent on the "target number".
 x = (the target number  20). Therefore if the target is 39, x = (3920) = 19.
 Fill in x and also (x1), (x+1) and (x+2) in the indicated places.
8  11  x  1 
x1  2  7  12 
3  x+2  9  6 
10  5  4  x+1 
This completed square adds up to 39 in just about every way you can think of.
Look at the diagram below for help!

8  11  19  1 
18  2  7  12 
3  21  9  6 
10  5  4  20 


