Visual Tcl was written and is copyrighted by Stewart Allen 
(stewart@neuron.com). More information can be found at 
http://www.neuron.com/stewart/vtcl.
Visual Tcl is written entirely in Tcl/Tk and covered by the GNU     
General Public License. 
Packaged for R by Guido Masarotto (guido@stat.unipd.it).