By the late 1970s the term "portaledge", which combines the words "portable" and "ledge", had become the common name for the typology. The originator of the term remains unknown to this day. Mike Graham, a famous American climber, founded his climbing gear company Gramicci in 1977. Over the next five years Graham sold over five hundred of the first commercially available portaledges, called Cliff Dwellings, to climbers in California and Europe. Graham made his Cliff Dwellings using equipment that he carried in his truck, and would set up his shop in friend's garages and basements. Graham's frame tubes slotted into each other at their corners, which allowed the frame to collapse into the smallest bag possible. His minimal corner connections were an important innovation, but they also made the Cliff Dwelling vulnerable to structural failure under extreme forces of nature. For an expedition to Patagonia in 1979 Graham designed the Fortress, the first portaledge large enough for two people. This model was constructed with ballistic nylon, a fabric strong enough to deflect small pieces of falling ice and rock. During the same year Graham made, but never tested, a prototype of a Windshield: a tent, suspended below the Cliff Dwelling that would deflect upward winds away from the portaledge.