%FUNCTION SELECTION
%
%   The existence of multiple functions allows the DRAW
%FRACTAL command to create non-trivial fractal images.
%The control box labeled "Function #" allows the user
%easy access to each of the functions created.  The
%slider control lets the user move from function to 
%function.  Only one function can be analysed and modified
%at a time.  The number of this "current function" is 
%displayed at the top of the box.  The current function may
%also be selected by clicking the mouse over its figure
%(see GRAPHICS WINDOW).
%   The FUNCTION ON check box allows the user to turn the
%current function "on" and "off".  In the "off" state, a
%function's box will only appear in the graphics window
%when it is the current function, and will not be included
%when the fractal is drawn.  This way, the user can easily
%try drawing fractals with and without certain functions
%in the system.  Note that if a function goes "out of
%bounds" (i.e. if any corner lies outside the unit square),
%the FUNCTION ON box is automatically turned of, and can
%not be turned on until the function is brought back "in
%bounds" (when a function is brought back in bounds, the
%FUNCTION ON box is automatically set to ON).  The FUNCTION
%ON setting is determined independently for each function.
%   The NEW button creates a new function, whose default
%value is the unit square, and whose function number is one
%greater than the previous highest value.  The new function
%becomes the current function.  Note: It is recommended
%that the user not leave any function as the unit square.
%Although it does not invalidate the fractal, it's presence
%will cause the fractal image to have fewer points plotted.
%   The COPY button makes a copy of the current function
%and assigns it a function number one greater than the
%previous highest value.  The new function becomes the
%current function.
%   The DELETE button deletes the current function entirely.
%