SET WINDOW -250,250,-250,250
RANDOMIZE
PLOT LINES:0,0
FOR k=0 TO 1000000
   LET a=RND
   IF a<0.5 THEN
      LET f=1
   ELSE
      LET f=-1
   END IF
   LET b=RND
   IF b<0.5 THEN LET x=x+f
   IF b>=0.5 THEN LET y=y+f
   PLOT LINES:x,y
NEXT k
END