C(25,12,2) = 7

Method of Construction: lexicographic greedy covering

Lower Bound: Schonheim

  1  2  3  4  5  6  7  8  9 10 11 12
  1 13 14 15 16 17 18 19 20 21 22 23
  2  3  4  5  6 13 14 15 16 17 24 25
  7  8  9 10 11 18 19 20 21 22 24 25
  2  3  4  5  6 12 18 19 20 21 22 23
  7  8  9 10 11 12 13 14 15 16 17 23
  1  2  3  4  5  6  7  8 12 23 24 25