Place twelve of the numbers 1 to 15 in the grid below such that:
1. The rows (a,b,c,d; e,f,g,h; i,j,k,l) have the same sum.
2. The columns (a,e,i; b,f,j; c,g,k; d,h,l) and the diagonals (a,f,k; b,g,l; c,f,i; d,g,j) all have the same sum.
Note: The rows do not have the same sum as the columns and diagonals.

a|b|c|d
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e|f|g|h
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i|j|k|l