PRINT "input Sierpinski number 3 to 12: M"
INPUT m
PRINT "input CYCLIC GAP 0 TO 2*M"
PRINT" EXAMPLE 1: 4,1---> NAZI CARPET"
PRINT "EXAMPLE 2: 4,4---> CROSS CARPET"
INPUT Q
SET MODE "color"
SET WINDOW 0,1920,0,1024
SET BACKGROUND COLOR "white"
LET x=1
LET y=1
LET c=0
LET s1=600
LET s2 =s1*1024/1920
DIM a(25),b(25)
FOR i=1 to m
    LET a(2*i-1)=cos(2*pi*i/m)
    LET b(2*i-1)=sin(2*pi*i/m)
NEXT i
FOR i=1 to m
    LET a(2*i)=(cos(2*pi*i/m)+cos(2*pi*(i-1)/m))/2
    LET b(2*i)=(sin(2*pi*i/m)+sin(2*pi*(i-1)/m))/2
NEXT i
PRINT "   GENERAL SIERPINSKI I.F.S. of second kind: CYCLIC GAP  driven "
PRINT "   BY R.L.BAGULA 23 feb 2002© copy rights reserved"
RANDOMIZE
PRINT "   M=";m
FOR n= 1  TO  2560000
    LET c =RND
    LET l=1+int(c*2*m)
    REM A simple example of driven IFS:
    REM since FIRST AND SECOND order points are alway two apart in this array
    REM a CYCLIC GAP  is imposed in the state machine
    REM by a modulo exclusion: odd numbers work first to second
    REM even numbers work first on first, second on second
    IF mod(d,2*m)<>mod(l+Q,2*m)  THEN
       LET d=l
       LET x1=x/3+(a(l)-b(l))/sqr(2)
       LET y1=y/3+(a(l)+b(l))/sqr(2)
    END IF
    LET x=x1
    LET y=y1
    SET COLOR 255
    IF n>10 THEN PLOT 1920/2+s1*x,1024/2+s2*y
    SET COLOR 32
NEXT n
END