Microsoft Surface chief Panos Panay Getty Images/Andrew Burton Microsoft is secretly working on a new Surface computer that would take on Apple's all-in-one iMac, reported DigiTimes and Windows Central last week.

This hypothetical Surface all-in-one, or "AIO," would reportedly be a slim, stylish Windows 10 desktop computer designed for the living room.

Given the Surface line's legacy in tablets and laptops, it seems safe to assume this AIO would have a touchscreen and probably a stylus.

There's more evidence to support the idea that a Surface AIO is coming: A Microsoft patent filing shows a design for a desktop PC that fits the bill.

In a more immediate indicator, software developer Shubhan Chemburkar visited Microsoft's Building 88 hardware labs over the weekend and noticed that the company is teasing new devices for 2016 and 2017, as noticed by The Verge.

The PC market is in an overall state of decline, but Microsoft has found some success bucking that trend with the Surface Pro tablet/laptop hybrid and Surface Book laptop — sleek, specialized devices that bring something new to the table.

For Microsoft to take on Apple's popular iMac line, it'll have to repeat the trick and figure out what it can do differently. The touch capability is a good start, and it would be nice to see a detachable tablet-like screen that you can take off and bring with you to the couch.

Apple's current iMac all-in-one computers. Apple

Still, a hypothetical Surface AIO would be yet another area where Microsoft would compete with the hardware manufacturer partners that build the vast majority of Windows computers. Companies like Dell and Samsung already make desktop all-in-one computers, and a Surface AIO would be taking those on, too. Still, the Microsoft party line has always been that Surface devices are intended to set the tone in the market as much as anything.

Finally, as for those other Surface devices hinted at in Chemburkar's photo: Rumors just won't die that Microsoft is working on a new Surface smartphone for release in 2017 that will be a serious contender with the iPhone. It seems that Microsoft is slowly but surely working to match Apple across every product category.

Microsoft declined to comment.