Make a colour blink

[Ulisses]

> Telling us what platform you're on, your OS, Python version and the 
> 
> actual GUI helps in cases like this.
> 
> 
> 
> -- 
> 
> My fellow Pythonistas, ask not what our language can do for you, ask
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> what you can do for our language.
> 
> 
> 
> Mark Lawrence

Hello again. I forgot to tell you: I'm in Windows OS, Python 3.4.1, using tkinter.