forces.netHowever, the device seems to have been powered off during the show, so it just looked like a helmet covered in triangular yellow tiles.This makes it hard to assess how well the system will work in practice, in particular how it copes with high contrast and changing light.Powered active camouflage, which relies on cameras to analyse the background and displays to copy it, will always be limited.It would be far better to have something more like the invisibility suits in Predator.This sort of magic always seemed as impossible as Harry Potter’s invisibility cloak, until the 1990s when British physicist John Pendry developed the theory for metamaterials, materials which can manipulate light in new ways.This sort of magic always seemed as impossible as Harry Potter’s invisibility cloak, until the 1990s when British physicist John Pendry developed the theory for metamaterials, materials which can manipulate light in new ways.Metamaterials could, in principle, bend light around an object so the light appeared to pass right through it, making the object invisible.Building a real-life invisibility cloak is challenging though. They need to be structured on a microscopic scale, and the designs so far are for rigid shells rather than flexible cloaks.Also, they tend to only work for a limited range of wavelengths. While there has been considerable progress with metamaterials in the microwave range, which could help aircraft disappear from radar, experts believe that practical invisibility in the visible range is still many years away.Some developers claim otherwise. In particular Guy Cramer, CEO of Canadian camouflage makers Hyperstealth, says that in 2011 he produced a Quantum Stealth technology which completely hides an object by bending all visible light around it.