That's right. You read the title right. This week is "No Writing" themed, which means no words, just creative thinking. Don't worry, the prompts all make perfect sense.
Visualize your main characters' face(s). Now, no matter your talent level, try to draw them. This should have you work out details that you might not think of- crow's feet, freckles, moles, small scars or acne, etc. If you can't picture your character well enough to be able to draw them (regardless of the end result) then you need to work on the particulars.