Matthew Somerville who made this has a bunch of other awesome things on his website - <a href="http://www.dracos.co.uk" rel="nofollow">http://www.dracos.co.uk</a><p>One I used just yesterday was for finding postboxes in the UK given a postcode - <a href="http://www.dracos.co.uk/play/locating-postboxes/" rel="nofollow">http://www.dracos.co.uk/play/locating-postboxes/</a>.