pro fern

;   Cyclosorus Fern

M1 = [  [0, 0,  0,   .25,  0,   -.4,  .02],$
    [.95,  .005,    -.005, .93,    -.002,  .5,  .84],$
    [.035, -.2,    .16,   .04,  -.09,    .02,   .07],$
    [-.04, .2, .16,    .04,   .083, .12,    .07]   ]

; Culcita (=Calochlaenia) dubia:

M2 = [  [0., 0., 0., .25,    0.,    -.14,  .02],$
    [.85,    .02,  -.02,    .83,   0,    1, .84],$
    [.09,    -.28,  .3,  .11, 0,  .6,  .07],$
    [-.09,    .28,   .3,   .09,  0,   .7,   .07]   ]


;    Asplenium adiantum-nigrum

M3 = [  [0,  0,   0,    .16,     0,    0, .01],$
    [.85,  .04, -.04,   .85,     0,   1.6,    .85],$
    [.2,   -.26, .23,    .22,     0, 1.6,    .07],$
    [-.15, .28,    .26,    .24,     0,    .44,   .07]   ]



M = M3

;a = FLTARR(4) & b = FLTARR(4) & c = FLTARR(4)
;d = FLTARR(4) & e = FLTARR(4) & f = FLTARR(4)


;a = [0., 0.95, 0.035, -0.04]
;b = [0., 0.005, -0.2, 0.2]
;c = [0., -0.005, 0.16, 0.16]
;d = [0.25, 0.93, 0.04, 0.04]
;e = [0.0, -0.002, -0.09, 0.083]
;f = [-0.4, 0.5, 0.02 ,0.12]

;wplot =  FLTARR(100,100)
window,0
;erase, 'ff9900'x
x = 0
y = 0
numits = 30000
scale = 25.
offsetx = 300
offsety = 100

FOR n = 1,numits DO BEGIN
    q = FIX(100. * Randomu(seed))
    IF (q GE 0) THEN k = 0
    IF (q GT 2) THEN k = fix(Randomu(seed)+ .5) + 2
    IF (q GT 16) THEN k = 1
    newx = M[0,k] * x + M[1,k] * y + M[4,k]
    newy = M[2,k] * x + M[3,k] * y + M[5,k]

;   newx = a(k) * x + b(k) * y + e(k)
;   newy = c(k) * x + d(k) * y + f(k)
    x = newx
    y = newy
    scalex = newx * scale + offsetx
    scaley = newy * scale + offsety
    IF (n GT 10) THEN plots,scalex,scaley,psym=3,color=36864L,/device
ENDFOR


END