So far, the features of VISU we described are fairly standard, and can be found in other less flexible visualization packages. However, the Tk library makes it possible to use our widget to build visualization hypertools, defined in John Ousterhout's book [4] as ``stand-alone applications which can communicate with each other and be reused in ways not foreseen by their original designers''. Indeed, it came as a surprise to us how easily the send command can be used by visualization tools based on the pict widget in peer-to-peer or master/slave relationships. In order to demonstrate the power of these hypertools, we take several examples.