(D I) (C H) | (A B) (F G)(D H) (C I) | (A F) (B G)-------------------------(A H) (F I) | (C D) (E G)(F H) (A I) | (D E) (C G)-------------------------(B I) (E H) | (C F) (A D)(B E) (H I) | (A C) (D F)-------------------------(B D) (G H)(D G) (B H)-----------(E F) (B C) (C E) (B F)-----------(E I) (A G)(G I) (A E)