(;GM[1]FF[4]SZ[6]
GN[Opposit set of black stone (R.clone().xor(F).neighbors4().expandTo(B).xor(B))]
PC[http://senseis.xmp.net/?BinMatrix]AP[GoWiki:2009]
DT[2012-08-19]
C[Diagram from http://senseis.xmp.net/?BinMatrix

Opposit set of black stone (R.clone().xor(F).neighbors4().expandTo(B).xor(B))]
PL[B]

AB[ea]


;
)
