C(9,3,2) <=12

Method of construction: affine geometry covering

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