These two bricks combined make a perfect inkwell and quill.
I got them in the Creator set with the brick-built moose and as far as I know – from a quick research on bricklink – the combination only occurs in one other set: The Elves Starlight Inn (41174). (Please let me know if I’m mistaken!)
Then I checked what else the “inkwell brick” is used for – Lego must have made it for a reason. It turns out it is frequently used in Friends/Elves/Disney Princess sets for displaying all those accessories for the figures; bows, tiaras etc. They fit in the hole in the hair pieces, but apparently you need somewhere to put them, when they are not used – and that’s where our brick comes in. The Friends Party Gift Store (41113) is a good example:
It’s also been used as side-view mirrors, a lid and a camera lens. A nice little brick in my opinion.