(;SZ[4]AW[ac]AW[ad]AW[bd]AB[cd]AB[cc]AB[dd]AB[aa]AB[ba]AW[ca]AW[da]AW[bb]C[FORCE]AP[goproblems]
(;B[bc]C[FORCE];W[cb]C[FORCE];B[ab]C[FORCE];W[ac])
(;B[cb]C[FORCE];W[ab]C[FORCE]
(;B[aa])
(;B[ba]C[FORCE];W[aa]C[FORCE]
(;B[bc]C[FORCE]
(;W[db]C[FORCE];B[ba]C[RIGHT])
(;W[dc]C[FORCE]
(;B[ba]C[RIGHT])
(;B[db]C[FORCE];W[dc])))
(;B[db]C[RIGHT])
(;B[dc]))
(;B[bc]C[FORCE]
(;W[ba])
(;W[db])
(;W[dc]))
(;B[db]C[FORCE];W[ba])
(;B[dc]C[FORCE]
(;W[aa])
(;W[ba])
(;W[bc])))
(;B[db]C[FORCE]
(;W[ab])
(;W[bc])
(;W[cb]))
(;B[dc]))