Trees painted on a book page. the tree is unpainted, and the "negative space" is what gets colored. OR could carefully cut out negative space on a page or two, making the tree really seem to stand out more.
Talvinen maisema --- Another great idea for teaching value using shades and tints. The original poster of this project, art teacher Jessica Young, gives a great explanation of the steps and tips she used with her fourth-grade students.