This page makes use of the
*tcl/tk* toolkit plugin which you can obtain from the here
. If you're ready you'll be able to read the ticker on
this page: examples. Alternatively you can download the code directly here.

The example *tcl/tk*
application shown here is a simple network creator. You use the mouse
buttons as follows:

**button-1**- create a node;**button-2**- select a node for joining (or double-button-1);**button-3**- drag a node around;- complete the network (saves lots of laborious connecting up);*complete*- find the shortest path (pink whilst calculating, orange when finished).*shortest path*

This simple illustration enables you to see how quickly the time taken for a brute-force solution to the shortest-path problem grows with the number of nodes. I suggest you start at 6 and work up. Depending on the power of your machine you should be able to solve 12 to 17 - it can take a very long time!