
This example, written by Bill Roberts, employs the tksheet widget as a
custom widget. While tksheet is quite complex, almost 1 MB in the
install directory, very little code was required in the support module
to build this example. The tksheet was created by ragardner and can
be found at https://github.com/ragardner/tksheet. Unfortunately, the
tksheet package was released with incomplete documentation.

I revised it to use the new module layout.

