Nicknamed the "Butterfly keyboard," it was a laptop keyboard from IBM introduced in 1995 on its ThinkPad 701C. When closed, the keyboard split apart and one part folded under the other enough to fit the smaller footprint of the case. When opened, it expanded to a full-size keyboard. See
ThinkPad and
TrackPoint.
The TrackWrite "Butterfly" Keyboard
Considered one of the finest examples of mechanical engineering on a portable computer, the TrackWrite lifted up and spread open to a full- size keyboard beyond the footprint of the laptop. (Image courtesy of Craig Leres.)