(;AB[ps]AB[pr]AB[pq]AB[pp]AB[po]AB[qo]AB[ro]AB[so]AW[sp]AW[rp]AW[qp]AW[qq]AW[qr]AW[rr]AP[goproblems]
(;B[sr];W[qs]
(;B[sq];W[ss];B[rs]C[Well done. Ko is the best result for black.RIGHT])
(;B[rs];W[ss]C[2-step ko. You can do better.])
(;B[ss];W[sq]))
(;B[rs];W[qs];B[sr];W[ss]C[2-step ko. You can do better.])
(;B[qs];W[rs]
(;B[sq];W[sr])
(;B[sr];W[sq]))
(;B[sq];W[sr]
(;B[qs];W[rs])
(;B[rs];W[qs])))