- Citrine is a relay that runs in your Android phone.

- Samiz syncs your local Citrine events with other people's Citrine events.

- Jumble displays a feed of that specific relay and allows you to post to that specific relay.

That way you get a hyperlocal "Nostr" with a feed of stuff only from people that are close to each other (and that they have decided to publish on that local feed, so presumably it will be things of interest to whoever is nearby).