http://www.carto.net/papers/svg/samples/canvas.shtml
http://64.233.179.104/search?q=cache:KilgAiNUWZsJ:www.w3.org/2002/Talks/www2002-svgtut-ih/hwtut.pdf+svg++tutorial&hl=it&gl=it&ct=clnk&cd=8&ie=UTF-8