Hey Seb,
Sorry for the delayed response, I’m only loosely attached to this project and didn’t have easy access to the previews you’re requesting.
Here are two screen captures - first, showing (very roughly) what we would like to be able to do (the Collection inside the circle would be horizontally scrollable), and second, why we can’t do that right now…
We were just working on our experience design again today, trying to figure out how to deal with the dissonance between non-rectangular aspects of our design with the forcibly rectangular Collection boundaries. If it was possible to mask any element, group of elements, or Collection inside of a vector or alpha “shell” then such conversations would disappear, and we could honor our design more freely.