His name is Julian Beever, known for his 3d chalk art work around the world. His ground perspective art will will your mind away.
Remember he’s simply using chalk and a sidewalk!
http://www.metro.co.uk/news/article.html?in_article_id=71357&in_page_id=34
http://uk.youtube.com/watch?v=jg8hw-DgkRI&feature=related
