Now that same functionality is available to Apple iPhone (AAPL) users, thanks to an update that rolled out yesterday.

Cardboard is a cheap device made out of, well, cardboard, that allows people to hold their phones right in front of their eyes and watch 360-degree videos in all their stereoscopic glory.

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Of course, most videos in YouTube aren’t shot in this mode just yet, so Google’s workaround is to display them on a virtual screen, as if the user is watching a flatscreen TV. It’s a neat effect, although the quality can be poor depending on screen resolution.

Basically, it’s just a gimmick for now, but it does point to a future where people might habitually don a Cardboard-like device in order to watch 360-degree videos, and not have to take it off in order to watch traditionally-shot videos.

Google introduced Cardboard support to the iOS platform at the end of March, so all app developers can make their immersive videos work on the device.

For more on virtual reality, watch our video.

Google’s I/O developer conference starts Wednesday, so it’s quite possible that the company will have more to announce this week on the virtual-reality front.