first (X,Y) differences of the Barnsley's fern

Generating the Barnsley's fern and its firsts(X,Y) differences .

Generating the Barnsley's fern using the the following parameters :

-Probability values :P=[0.02 0.17 0.38 0.47]
Note that the interval [0.38 0.47] is skipped.

-Generating random values using the Uniform law.

-Sequence of coordinates (xn+1,yn+1) =:

--> 0.00 <= r < 0.02
(0.5, 0.32yn)
-->0.02 <= r <= 0.17
(-0.139xn+ 0.263yn+ 0.57 , 0.246xn+ 0.224yn- 0.036)
-->0.17 < r <= 0.38
(0.170xn - 0.215yn+ 0.408, 0.222xn+ 0.176yn+ 0.0893)
-->0.47 < r < 1
(0.781xn + 0.034yn+0.1075,-0.032xn+ 0.739yn+ 0.27)

-Number of iterations N=1e+6, Computing time : d < 1 second.

-First Order differences of each of the sequence (X_n,X_n) diff(X,Y) implies a sort of multiplication of the tree .

- Usage : [U,dU]=Barnsleyfern1d(filename1,filename2) plots the two figures and saves them with format specified by the filename.

References to other links :
http://en.wikipedia.org/wiki/Barnsley_fern
http://www.math.utah.edu/~doman/Fractals/Fern.m
http://www.mathworks.com/moler/exm/chapters/fern.pdf