Virtual reality
Around the same time, Douglas Engelbart used computer screens both as input and output devices. In 1968, Ivan Sutherland, with the help of many students including Bob Sproull, created what was widely considered to be the first head-mounted display (HMD) system for use in immersive simulation applications. It was primitive both in terms of user interface and realism, and the HMD to be worn by the user was so heavy that it had to be suspended from the ceiling. The graphics comprising the virtual environment were simple wire-frame model rooms. The formidable appearance of the device inspired its name, The Sword of Damocles.
SixthSense
SixthSense is a gesture-based wearable computer system developed at MIT Media Lab by Steve Mann in 1994 and 1997 (headworn gestural interface), and 1998 (neckworn version), and further developed by Pranav Mistry (also at MIT Media Lab), in 2009, both of whom developed both hardware and software for both headworn and neckworn versions of it. It comprises a headworn or neck-worn pendant that contains both a data projector and camera. Headworn versions were built at MIT Media Lab in 1997 (by Steve Mann) that combined cameras and illumination systems for interactive photographic art, and also included gesture recognition (e.g. finger-tracking using colored tape on the fingers).