SET MODE "color"
SET WINDOW 0,1920,0,565
SET BACKGROUND COLOR "white"

LET x=0
LET y=0
LET a=0
LET b =0
LET s1=210/2
LET s2 =s1*1024/1920
RANDOMIZE
PRINT"two squares space fill transformed as a Wright torus I.F.S."
PRINT"BY R.L.BAGULA 16 april 2004 ©"
FOR n= 1  TO  10000000
   LET a =RND
   LET r=sqr(2)
   IF a <= 1/2 THEN
      LET x1=y/r+3/2
      LET y1=-x/r+3/2
      SET COLOR "black"
   END IF
   IF  a<= 1 AND a>1/2 THEN
      LET x1=-y/r+1/2
      LET y1=x/r+1/2
      SET COLOR "blue"
   END IF
   REM Wright torus transforms
   IF rnd>0.5 then
      LET x=x1-2
      LET y=y1
   ELSE
      LET x=(x1-2)/((x1-2)^2+y1^2)
      LET y=y1/((x1-2)^2+y1^2)
   END IF

   IF n>10 THEN PLOT 1920/2+s1*x,1025/2+s2*y-250
NEXT n
END