This animation is part of my website [url=http://www.fransvanschooten.nl/bursa.htm]Bursa Science Festival / AstroFest (fransvanschooten.nl)[/url][br]or, in Dutch, [url=http://www.fransvanschooten.nl/utalent.htm]UTalent (fransvanschooten.nl)[/url][br][br]In a number of steps, the animation explains the geometrical principles of a sundial.