Those horribly bad covers are priceless. For some reason they remind me of old lifetime movies? As I'm researching and brainstorming for my book, I want to include everything on my cover. There is so much imagery and symbolism in Slaughterhouse Five, that trying to incorporate them all would have my book on one of those "worst book covers ever" blogs.
The keep it simple approach inspired me to research minimalist graphic design. I came across this site that has a history of the style: "A History of Minimalist Graphic Design." The examples are posters, but definitely relatable.
