If you are using a *nix operating system, Tk provides a demo/tutorial called widget:

shell_prompt% widget
[download]

providing the install set up the bomb path properly, otherwise try to 'locate' it first, it is there. :)

Jeff

R-R-R--R-R-R--R-R-R--R-R-R--R-R-R--
L-L--L-L--L-L--L-L--L-L--L-L--L-L--