I found this easy but very cool project on a wonderful blog called "TeachKidsArt". It was a very do-able project for my participants and they loved the 3-D results. A different spin on a Valentine's Day art project.
I chose this because though the form of the tree is one, there are different styles of drawing in each square, as some are more smooth, some are swirly, colourful, and with no colour. It has a variety of different of art styles.