The black background! It got 53% of the votes.
With the white one as runner up, which got 38% of the votes:
Thanks to all 104 of you who voted. I will get both the black design and a simplified version of the white design printed and let you know when they are ready to buy on my Etsy shop.
p.s. Everyone who shared on Facebook or retweeted on twitter, let me know because you need to claim your prizes!