(;GM[1]FF[4]SZ[19]
GN[Black 4 at 1]
PC[http://senseis.xmp.net/?SnapbackProblem16/Solution]AP[GoWiki:2009]
DT[2009-04-22]
C[Diagram from http://senseis.xmp.net/?SnapbackProblem16/Solution

Black 4 at 1]
PL[W]

AB[oo][po][qo][ro][so][op][sp][mq][oq][qq][rq][nr][rs]
AW[pp][qp][rp][pq][or][pr][qr][os][qs]

;W[sq]C[W1]MN[1]
;B[sr]C[B2]MN[2]
;W[rr]C[W3]MN[3]
;B[sq]C[B4]MN[4]

;
)
