This is from a particular scene in Way of Kings, where Shallan sees strange creatures appearing in her drawings. I always pictured them as sort of spirograph heads, which is what I used to draw them in this illustration. (Which, I found that doing complex spirographs was much harder than I had anticipated and I think I practiced a dozen times before attempting to draw them in this illustration.) As an artist, finding things appearing in my drawings would be truly terrifying! *laugh*