(;AB[ad]AB[bd]AB[cd]AB[dd]AB[dc]AB[db]AB[da]AW[ac]AW[bc]AW[cc]AW[cb]AW[ca]LB[fa:A]LB[af:D]C[If you think that white is already alive, press 'A'; If you think that white is already dead, press 'D'; If you think that you can kill white or create a ko or seki, click the correct point.]AP[goproblems] (;B[af]C[] (;W[bb]C[CHOICE];B[aa]C[Good job! A 2 by 2 square is always dead.RIGHT]) (;W[ab]C[CHOICE];B[ba]C[Good job! A 2 by 2 square is already dead.RIGHT]) (;W[aa]C[CHOICE];B[bb]C[Good job! A 2 by 2 square is always dead.RIGHT]) (;W[ba]C[CHOICE];B[ab]C[Good job! A 2 by 2 square is always dead.RIGHT])) (;B[fa]C[Nope - the white group is already dead.]) (;B[bb]C[Nope - the white group is already dead.]) (;B[ba]C[Nope - the white group is already dead.]) (;B[aa]C[Nope - the white group is already dead.]) (;B[ab]C[Nope - the white group is already dead.]))