Some great math-oriented artwork by my friend Hop David. He's a math-oriented illustrator, and also do mural work and folk art.
The following is one of my top 5 favorites of his drawings. It's mixed with math and humor, in a subtle way.
Here's Hop's Gallery http://www.clowder.net/hop/. Hundreds of artwork there. Check it out. If you have young kids, i'd recommend Hop's coloring books there.
He's also on Hop David facebook and Hop David amazon.com author page.