Shading Assignment Suggestions
The assignment suggestions are not listed by age or difficultly level but, of course, the instructor or the person completing the assignments can decide to what degree any assignment should be done.
John Ruskin's Book
The Elements of Drawing: in three letters to beginners.
Shown here- a photograph of my hard copy of John Ruskin's Book.
If you decide to use "The Elements of Drawing: in three letters to beginners.", you may (if the pdf is still available) read it online at http://www.gutenberg.org/ebooks/30325, or do as I did and purchase a hard copy which is pictured on this page.