We've seen from patent filings and leaked timelines that Microsoft seems to be working on a dual-screen handheld device codenamed Andromeda. Some new APIs found in the latest Windows 10 preview provide more evidence, even offering clues as to its capabilities.

Twitter user WalkingCat spotted an API for devices with two screens and a hinge. Applications can query the orientation of the two screens and the position of the hinge. The hinge's position is reported as being one of several options: closed, concave, convex, flat, and full.

This points at not just a hinge but a 360-degree hinge similar to those found on Lenovo's Yoga laptops and HP's various 360 systems. Further, it implies that the new device will have some functionality when fully closed or when opened all the way up with a screen showing front and back.

This API does still leave one big mystery about the device. Rumor suggests that Microsoft wants the device to have a comparable role to that of the Surface Pro—pushing a new form factor that will then be iterated on by other PC OEMs. Surface Pro achieved this through proving its value as a lightweight PC that was particularly strong for things like note-taking. Andromeda's form factor is expected to be comparable to that of a smartphone (and it should support both mobile data and telephony, further cementing that similarity), but it will continue to suffer from Windows' problem in the smartphone space: a lack of applications.

While dual screens and hinge will be novel, a novel feature isn't reason enough to buy a new device. It has to be useful, too. Does Andromeda qualify? That's something this API doesn't tell us.