The touchscreen was hacked together with PCs, video cameras, projectors and cheap infrared illuminators. It can handle 100 simultaneous touch points and has a curvature of 135 degrees. The display is used to teach mathematics and computer science students at the University of Groningen, in the Netherlands. It works like this: “The cameras are all placed behind a large, cylindrical screen (formally used as a 3D theater) due to the front side of the screen, the cameras cannot see clearly through the screen”
Source: https://thehackernews.com/2011/02/worlds-largest-touchscreen-hacked.html