SET WINDOW -10,10,-10,10
SET COLOR mode "NATIVE"
SET AREA COLOR colorindex(245/255,210/255,90/255)
PLOT AREA : -10,-10;10,-10;10,10;-10,10
SET AREA COLOR colorindex(0/255,0/255,0/255)
SET COLOR 1
DRAW GRID2(10,10)
SET LINE WIDTH 3
PLOT LINES:-9,9;9,9
PLOT LINES:-9,-9;9,-9
PLOT LINES:-9,-9;-9,9
PLOT LINES:9,-9;9,9
DRAW DISK WITH SCALE(1/10)*SHIFT(6,6)
DRAW DISK WITH SCALE(1/10)*SHIFT(6,0)
DRAW DISK WITH SCALE(1/10)*SHIFT(6,-6)
DRAW DISK WITH SCALE(1/10)*SHIFT(0,6)
DRAW DISK WITH SCALE(1/10)*SHIFT(0,0)
DRAW DISK WITH SCALE(1/10)*SHIFT(0,-6)
DRAW DISK WITH SCALE(1/10)*SHIFT(-6,6)
DRAW DISK WITH SCALE(1/10)*SHIFT(-6,0)
DRAW DISK WITH SCALE(1/10)*SHIFT(-6,-6)
DIM M(19,19)
FOR i= 1 TO 19
   FOR j=1 TO 19
      LET M(i,j)=2
   NEXT j
NEXT i
LET M(16,4)=3
SET AREA COLOR colorindex(0/255,0/255,0/255)
DRAW DISK WITH SCALE(1/2.3)*SHIFT(16-10,6)
LET M(4,4)=1
SET AREA COLOR colorindex(255/255,255/255,255/255)
DRAW DISK WITH SCALE(1/2.3)*SHIFT(4-10,10-4)
LET M(16,16)=3
SET AREA COLOR colorindex(0/255,0/255,0/255)
DRAW DISK WITH SCALE(1/2.3)*SHIFT(16-10,10-16)
LET M(4,16)=1
SET AREA COLOR colorindex(255/255,255/255,255/255)
DRAW DISK WITH SCALE(1/2.3)*SHIFT(4-10,10-16)
LET M(6,3)=3
SET AREA COLOR colorindex(0/255,0/255,0/255)
DRAW DISK WITH SCALE(1/2.3)*SHIFT(6-10,10-3)
LET M(4,6)=1
SET AREA COLOR colorindex(255/255,255/255,255/255)
DRAW DISK WITH SCALE(1/2.3)*SHIFT(4-10,10-6)
END

EXTERNAL PICTURE GRID2(n,m)
SET LINE STYLE 3
FOR i=-1*n TO n
   PLOT LINES:i,-1*m;i,m
NEXT i
FOR j=-1*n TO n
   PLOT LINES:-1*n,j;n,j
NEXT j
SET LINE STYLE 1
END PICTURE