Here is The Girl's piece - sorry it is a little blurry!
As you can see, The Boy decided to combine the color drawing with some work in perspective!
And yes, I made one too. I had fun layering the crayon!
There are plenty more projects in the book I linked above. The author describes the exercises as "painting with crayons", and you only use eight colors, ever... black, brown, red, orange, yellow, green, blue, purple --- the basic 8-pack of Crayola. We used art paper for this, with a heavier texture than regular paper.