I sketched these a while ago and, having found my tablet, made them a reality! I changed the Reviews icon entirely, as the faces are much cuter and less awkward than the thumbs-up-thumbs-down idea.
I had to experiment with sizes, and ended up making a few sizes in case I change my mind.
I based the Art Discoveries icon off of the famous artwork, “Lily Brik, 1924”, by Alexander Rodchenko. The cover of Franz Ferdinand’s album You Could Have It So Much Better and Stephen Colbert’s “Cold War Update” montage borrow from this image.