These are great. Nice hidden treat to delight users. =)
Mary <3 <3 <3
These animations are awesome.
UX Feedback, though: You should never rely on an animation like this to convey that something is a folder or a grouping. These animations all rely on hover, which touch devices really don't have. Don't make the user hover everything on your page to see what it means. / my 2 cents
I agree. They're nice, but if the goal is to explain "this is a set of things," it should be illustrated statically, not upon hover.