Mouth of Flower - Octavio Ocampo This is good art because it is an optical illusion. It could either be just some flowers with a butterfly, or you can also see a woman's face. It is very creative in a subtle way.
These colorful geometric murals were done by Matt W. Moore, an amazing graffiti artist who can blend shapes, colors and street art all in one. Check out this post for some really awesome graffiti murals all over the globe.