This is one bit of a larger 19x19 game (not pictured) where black's bad shapes all over the board allowed white to come back from what should have been a certain loss.
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[19]KM[0.50]
PW[White]PB[Black]AW[ma][oa][mb][nb][mc][md][nd][od][sd][pe][qe][re][se]AB[ob][nc][oc][rc][sc][pd][qd][rd]TR[oa]C[White just played the marked stone. Can black salvage the situation?]
(;B[qb]LB[pb:A][pc:B]TR[sb][qc]C[RIGHT
Black has room for eyes now. A and B are miai for life.])
(;B[pb]
;W[qb]
(;B[pa]
;W[qa]
(;B[na]
;W[pc]
;B[qc]
;W[oa]C[Ko should be unacceptable. Black can do better.]
;B[pc]
;W[rb]LB[ra:A][sb:B]C[White can either kill at T18 immediately or make a dead shape for black at S19. Black has no choice but to die now.])
(;B[pc]
(;W[na]LB[ra:A][rb:B]C[CHOICE
Black has A or B to start a ko; however, black can do better.])
(;W[rb]C[CHOICE
White gets to give Black a dead shape.])))
(;B[rb]
;W[pa]CR[sa]LB[qa:A][pc:B]C[White has either A or B to leave black with only one eye.])
(;B[pc]
;W[pa]C[W safely connects out and B dies.]))
(;B[pc]
;W[qb]
;B[pa]
;W[na]
(;B[qa]
;W[pb]C[Whoops])
(;B[pb]LB[qa:A][rb:B]C[White can use A or B, and the best result for Black is then a ko; however, Black can do better than ko.]))
(;B[pa]
;W[pb]
(;B[na]
;W[pc]C[Ouch ;)])
(;B[pc]
;W[qa]
;B[qb]
;W[ra]C[Black can do better than start a ko.])))