Vladimir Nabokov offers our favorite tribute to the joys of coloring with a white crayon or pencil:
"The white one alone, that lanky albino among pencils, kept its original length, or at least did so until I discovered that, far from being a fraud leaving no mark on the page, it was the ideal implement since I could imagine whatever I wished while I scrawled." (
Speak: Memory, revised edition, 1967)
See, of course, our own
Minimalist Coloring Book.