Google’s newly announced Cloud Anchors help users place virtual content in the same real world location that can be seen on different devices. You can grab the simple, fun, open-source Just A Line app for iOS and Android to take it for a spin with a friend, or just to sketch in space solo:
Just put two phones side-by-side and tap the partner icon. Once the phones are connected, you and your partner will be able to see, and contribute to, the same drawing.
This makes Just a Line the first app that lets two people create together in AR, at the same time, across Android and iOS.