Here is the website that contains many chalk arts (I don't want to hotlink so many images). Check it out, they are truly amazing.
http://www.owlsprings.com/chalk/ChalkIndex.htmlHere are a few examples of the images looking from a different angel.
Lady in a Pool
Lady in a Pool seen from the wrong angle
"Make Poverty History" viewed as intended
Make Poverty History drawing from the side(40 ft long)