Interesting! I've been thinking about how you'd best teach sentence patterns for a long time, happy someone is making progress on it.

I'm a bit too beginner to effectively use the app, sadly, but it's quite an interesting flow.

As an aside, a while ago, I sort of prototyped the reverse: Learn vocab to understand a natural language sentence, translate the sentence (https://infi.koljasam.com)

Happy to talk and exchange notes, if you want :)