What does an Android co-founder do days before a big announcement of a major Android phone? When you are Andy Rubin, it's apparently tease people with another potentially beautiful device of the future.

Rubin, who is now the founder and CEO of the startup Playground, tweeted out a photo of what looks like a phone that he is "really excited" about on Monday.

Based on this tiny glimpse, the device might be just one big screen.

While all we get is a corner of the device, it's a corner that looks very much like the Xiaomi Mi Mix -- a beautiful phone with a gorgeous, edgeless display. That Xiaomi phone is only available in China, though.

Any other details are just going to have to wait until Rubin, or anyone he is working with is ready to share. Playground didn't immediately respond to a request for comment.