Test Yourself!

My bread-and-butter is making art for educational publishing.  To denote different learning sections of a book, I get requests to create icons of various sizes and complexities.  Often, rather than getting a detailed description of what each icon will be, I simply get a list of sections for a book with little to no description.  Not only is it "reinventing the wheel" again and again but it's usually so vague it might as well say "draw the air."  
Anyway, the latest list said things like: Living Image, Primary Source, and Test Yourself.  I simply drew the first thing that popped into my head.  It wasn't approved....