
c	A small "fun" test program for the VT125: fractals!

	Program FRACTALS

	cx=140
	cy=96
	x=.50001
	y=0

	type *,'What is lambda?(x,y)'
	accept *,lx,ly
	call fol(s,lx,ly)
	type *,'what is scale'
	accept *,sc
	call init
	call scale(-300.,300.,-300.,300.)
	sc=2*cx/sc

	do 10 i=1,10
	  call funxy(x,y,lx,ly)
10	continue

20	call pl(sc,x,y,cx,cy)
	call funxy(x,y,lx,ly)
	goto 20

	stop
	end


	subroutine pl(sc,x,y,cx,cy)

	xt=sc*(x-.5)+cx
	yt=cy-sc*y
	call draw(xt,yt)

	return
	end


	subroutine qrt(x,y,s)

	t=y
	s=sqrt(x*x+y*y)
	y=sqrt((-x+s)/2)
	x=sqrt((x+s)/2)
	if(t.lt.0)x=-x

	return
	end


	subroutine fol(s,lx,ly)

	s=lx*lx+ly*ly
	lx=4*lx/s
	ly=-4*ly/s

	return
	end


	subroutine tl(x,y,lx,ly)

	tx=x
	ty=y
	x=tx*lx-ty*ly
	y=tx*ly+ty*lx

	return
	end


	subroutine funxy(x,y,lx,ly)

	call tl(x,y,lx,ly)
	x=1-x
	call qrt(x,y,s)
	rr=ran(int(x))
	if(rr.ge.0.5)goto 30
	x=-x
	y=-y
30	x=1-x
	x=x/2
	y=y/2

	return
	end
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