

Piece of metal with bunnies found at train station
I found this little piece of metal with enamel depicting two white bunnies fucking(?) I think. Looks like it could have been a pin, though it must be broken then cause there is no way to pin it.
My question is, what does it mean? Is it some sort of logo of a brand or an organization or does it have some meaning in some culture? Also why does the one in the front look so sad?