It's sometimes hard to remember how far virtual reality has come in recent years. Not just in terms of technical achievement (though that's impressive), but also mainstream awareness. The idea of strapping a VR headset to your face is so common now, that Kellogg's is offering cardboard goggles with its breakfast cereal. A new promotion for Nutri-Grain in New Zealand lets customers construct their own headset from a cereal box, with the display provided by their smartphone. An official app offers access to a handful of 360-degree VR experiences including wingsuiting and a downhill mountain bike ride. Although we've not been able to try these for ourselves (you need to scan a QR code from the cereal box), the iOS and Android app does include a brief teaser.

It's possible to argue that this is as misleading as old "holographic" cereal toys that used to be little more than shiny images with multiple viewpoints. (Yes, it's technically holographic, but it's not what people think of when they imagine holograms.) However, this sort of virtual reality experience is nearer to fully-immersive sci-fi VR than perspective-changing pictures are to full, 3D holograms. It also shows how important smartphones could be for enabling mainstream virtual reality. Cardboard virtual reality goggles are far from perfect, but for such a cheap solution they're surprisingly usable. All you need is your mobile phone, a cereal box, a knife, scissors, and some sticky tape.