Try moving the mouse over the screen...
Click to make THE butterfly bigger...
F
L
U
T
T
E
R
B
Y

( You need to enable Java to see this applet. (Allow Blocked Content) )

here is the source code... feel free to play with it...
I started with someone elses program...a tutorial...
so I guess it's open-source now! the java file
the class file
right click and save target as...