(;AP[goproblems]AB[ab]AB[bc]AB[cb]AB[ba]AW[ae]AW[be]AW[bd]AW[cd]AW[cc]AW[dc]AW[db]AW[eb]AW[ea](;W[ac];B[ad]MA[ac](;W[ca];B[da]MA[ca]C[](;W[ac]C[Double Ko, black cannot win them bothRIGHT])(;W[ca]C[NOTTHIS]))(;W[da];B[ca]C[Ko is not best])(;W[ac]C[NOTTHIS]))(;W[ca];B[da]MA[ca](;W[ac];B[ad]MA[ac](;W[ca]C[RIGHT])(;W[ac]C[NOTTHIS]))(;W[ad];B[ac]C[Ko is not best])(;W[ca]C[NOTTHIS]))(;W[ad];B[ac](;W[ca];B[da]C[Ko is not best])(;W[da];B[ca]C[Black is alive]))(;W[da];B[ca](;W[ac];B[ad]C[Ko is not best])(;W[ad];B[ac]C[Black is alive])))