This code came from http://www.cs.bris.ac.uk/~lg7702/spd/ License Agreement This software is freely distributable, so long as it is kept in its current form. The code may not be reused or altered without the specific permission of either the authors as defined below, or the University of Bristol Department of Computer Science. Neither Bristol University or the authors accept any responsibility for any harm caused by this software in normal use, or mis-use. 1. The authors are defined as the members of this Software Product development group, that is Luke Goodrich, Dan Archbold, and Brendan Abott. 2. By the software we define the executable file contained in the downloadable zip file. The other components contained are copyright Microsoft Corporation, and are freely re-distributable under their licensing agreements with software developed with their tools.