if color4~=M(rx+1,ry)           %1,0
      M(rx+1,ry)=color2; end;
 
if color4~=M(rx,ry+1)           %0,1
      M(rx,ry+1)=color2; end;
 
if color4~=M(rx+1,ry+1)           %1,1
      M(rx+1,ry+1)=color2; end;
   
if color4~=M(rx-1,ry)           %-1,0
      M(rx-1,ry)=color2; end;
   
if color4~=M(rx,ry-1)           %0,-1
      M(rx,ry-1)=color2; end;
   
if color4~=M(rx-1,ry-1)           %-1,-1
      M(rx-1,ry-1)=color2; end;
 
if color4~=M(rx-1,ry+1)           %-1,1
      M(rx-1,ry+1)=color2; end;
   
if color4~=M(rx+1,ry-1)           %1,-1
      M(rx+1,ry-1)=color2; end;
   