### Composite, Simple

Use 3x3 the 4x4 magic square and the '4x4 blown up' 3x3 magic square to produce a (simple) 12x12 magic square.

Take a number from the first grid and add (number -/- 1) x 16 of the same cell from the second grid.

1x number

 1 8 13 12 1 8 13 12 1 8 13 12 15 10 3 6 15 10 3 6 15 10 3 6 4 5 16 9 4 5 16 9 4 5 16 9 14 11 2 7 14 11 2 7 14 11 2 7 1 8 13 12 1 8 13 12 1 8 13 12 15 10 3 6 15 10 3 6 15 10 3 6 4 5 16 9 4 5 16 9 4 5 16 9 14 11 2 7 14 11 2 7 14 11 2 7 1 8 13 12 1 8 13 12 1 8 13 12 15 10 3 6 15 10 3 6 15 10 3 6 4 5 16 9 4 5 16 9 4 5 16 9 14 11 2 7 14 11 2 7 14 11 2 7

+ (number -/- 1) x 16

 2 2 2 2 9 9 9 9 4 4 4 4 2 2 2 2 9 9 9 9 4 4 4 4 2 2 2 2 9 9 9 9 4 4 4 4 2 2 2 2 9 9 9 9 4 4 4 4 7 7 7 7 5 5 5 5 3 3 3 3 7 7 7 7 5 5 5 5 3 3 3 3 7 7 7 7 5 5 5 5 3 3 3 3 7 7 7 7 5 5 5 5 3 3 3 3 6 6 6 6 1 1 1 1 8 8 8 8 6 6 6 6 1 1 1 1 8 8 8 8 6 6 6 6 1 1 1 1 8 8 8 8 6 6 6 6 1 1 1 1 8 8 8 8

= (simple) 12x12 magic square

 17 24 29 28 129 136 141 140 49 56 61 60 31 26 19 22 143 138 131 134 63 58 51 54 20 21 32 25 132 133 144 137 52 53 64 57 30 27 18 23 142 139 130 135 62 59 50 55 97 104 109 108 65 72 77 76 33 40 45 44 111 106 99 102 79 74 67 70 47 42 35 38 100 101 112 105 68 69 80 73 36 37 48 41 110 107 98 103 78 75 66 71 46 43 34 39 81 88 93 92 1 8 13 12 113 120 125 124 95 90 83 86 15 10 3 6 127 122 115 118 84 85 96 89 4 5 16 9 116 117 128 121 94 91 82 87 14 11 2 7 126 123 114 119

I have used method composite, simple to construct

12x12, Composite, Simple.xls