(;AB[ba]AB[ca]AB[fa]AB[fb]AB[cc]AB[dc]AB[ec]AB[ad]AB[bd]AW[ac]AW[bc]AW[bb]AW[cb]AW[db]AW[ea]AP[goproblems]
(;B[aa];W[eb]C[bent 4 in the cornerRIGHT]
(;B[ab];W[da];B[ba];W[aa];B[ab]C[bent 4 in the cornerRIGHT])
(;B[da];W[ab]))
(;B[eb];W[aa];B[ab]C[Adv. koCHOICE]))