[plt-scheme] Simple UI for delivering simple functionality

I have a few functions I'd like to send to a couple of non-programmer
friends.  I can package up an app such that *I* could use it, but I'd
like to avoid triggering their parenthesis-allergies  I could use a
simple graphical form with some text fields, or I could use something
readline-oriented.  One target environment is Mac OS X, the other is
Windows XP.

I would like to avoid having to become an expert on how to draw, fill,
and place various kinds of geometrical objects, unless that is really
necessary.  Are there functions in the libraries somewhere that would
enable me to create a form, place a few text fields on it, and read/
write strings from/to those fields?

Or I could use getline, but then apparently I need to be sure the
proper libraries exist on the target machine.

If experience is any guide, I'm likely overthinking this and there's a
completely simple way to accomplish it.  Insights are invited.

-jmc