(;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[db][bc][dc][cd][dd]
AW[cb][eb][gb][ec][ed][be][ce][de][ee][bg]

;B[ca]C[B2]MN[2]
;W[ba]C[W3]MN[3]
;B[da]C[B4]MN[4]
;W[bb]C[W5]MN[5]
;B[bd]C[B6]MN[6]
;W[ab]C[W7]MN[7]

;
)
