'===========================================================================
' Subject: FRACTAL FERN                      Date: 07-12-96 (22:42)       
' Author:  Andy J. Golden                    Code: QB, QBasic, PDS, PB    
' Origin:  YHBV44B@prodigy.com             Packet: GRAPHICS.ABC
'===========================================================================
' IFSFERN.BAS
SCREEN 2
CLS
VIEW (0, 0)-(639, 199)
WINDOW (-4, 0)-(6, 10)
RANDOMIZE TIMER
X = 0
Y = 0
WHILE INKEY$ = ""
R = RND
IF (R <= .01) THEN
    A = 0: B = 0: C = 0: D = .16: E = 0: F = 0
ELSEIF R > .01 AND R <= .86 THEN
    A = .85: B = .04: C = -.04: D = .85: E = 0: F = 1.6
ELSEIF R > .86 AND R <= .93 THEN
    A = .2: B = -.26: C = .23: D = .22: E = 0: F = 1.6
ELSE
    A = -.15: B = .28: C = .26: D = .24: E = 0: F = .44
END IF
NEWX = (A * X) + (B * Y) + E
NEWY = (C * X) + (D * Y) + F
X = NEWX
Y = NEWY
PSET (X, Y)
WEND
SCREEN 0