This is a pair of heart shaped gears. You can see the movie to find how does it works. The gear is basically a non-circular gear (NCG)
When you look at the shape of a heart, you will find that there is a tip and a pit. "they can match", when the idea flashed through my mind, I realize that I can design a pair of gears with same heart shape(I'm major in mechanical engineering), and here is it, a pair of eardrops(without hooks).
I think it is a good idea to give such a gift to your lover. It is a perfect annotation of "My heart follows you".
If you want the gears turn like in the video, you need to order the axis pair
and drill two d=2mm holes with a distance of 16.5mm on some flat base by yourself.