(;GM[1]FF[4]SZ[19]
GN[Black mistake]
PC[http://senseis.xmp.net/?ShapesRelatedToTheCarpentersSquare]AP[GoWiki:2009]
DT[2009-05-27]
C[Diagram from http://senseis.xmp.net/?ShapesRelatedToTheCarpentersSquare

Black mistake]
PL[W]

AB[da][db][bc][dc][cd][dd]
AW[bb][cb][eb][gb][ec][ed][be][ce][de][ee][bg]

;B[bd]C[B4]MN[4]
;W[ab]C[W5]MN[5]
;B[ba]C[B6]MN[6]
;W[ca]C[W7]MN[7]
;B[ac]C[B8]MN[8]
;W[ea]C[W9]MN[9]

;
)
