SET MODE "color"
SET WINDOW 0,785,0,565
SET BACKGROUND COLOR "white"
LET x=0
LET y=0
LET a=0
LET b =0
LET s1=310/2.
LET s2 =s1*565/785
RANDOMIZE
PRINT"five point attractors I.F.S."
PRINT"BY R.L.BAGULA 19 June 1998 ©"
FOR n= 1  TO  2000000
    LET a =RND
    IF mod(n,5)>0 then
       LET r=-sqr(5)
    ELSE
       LET r=sqr(5)
    END IF
    LET x2=x1
    LET y2=y1
    LET p=int(1-2*rnd)
    IF a <= 1/5 THEN
       LET x1=x/r-((1+sqr(5))/2+p )
       LET y1=y/r
    END IF
    IF  a<= 2/5 AND a>1/5 THEN
       LET x1=-x/r -(1+sqr(5))/2
       LET y1=-y/r
    END IF
    IF  a<= 3/5 AND a>2/5 THEN
       LET x1=-x/r -((1+sqr(5))/2-1)
       LET y1=-y/r
    END IF
    IF  a<= 4/5 AND a>3/5 THEN
       LET x1=y/r
       LET y1=x/r +1
    END IF
    IF  a<= 1 AND a>4/5 THEN
       LET x1=-y/r
       LET y1=-x/r  -1
    END IF
    LET x0=x
    LET y0=y
    LET x=x1
    LET y=y1
    LET r=sqr(x*x+y*y)
    LET r0=sqr(x0*x0+y0*y0)
    REM approximate second derivative Laplacian
    REM Kigami/ Lapidus :d^2u/dz^2=-k*u
    LET xu= (x-2*x0+x2)/(r-r0)^2
    LET yu= (y-2*y0+y2)/(r-r0)^2
    LET ru=sqr((xu-x)^2+(yu-y)^2)
    REM   Laplacian domain  
    if mod(int(r*ru),2)=0 then SET COLOR 256-mod(int(r*ru),255) 
                          else set color 1+mod(int(r*ru),255)
    IF n>10 THEN PLOT 785/2+s1*x+100 ,565/2+s2*y
NEXT n
END