Whiteboard
Whiteboards became commercially available in the early 1960s, but did not become widely used until 30 years later. Early whiteboards needed to be wiped with a damp cloth and markers had a tendency to leave marks behind, even after erasing the board. Dry-erase markers for whiteboards were invented in 1975.
RoughRider wheelchair
The earliest recorded history of a wheelchair was inscribed in stone on a Chinese Sarcophagus in the 6th century A.D. There have been many variations on the basic design since then but standard features always included rear wheels, front caster wheels, footrests, side frames and seating features. Until recently wheelchairs were designed for relatively smooth surfaces and paved streets and were not designed for rugged environments. Thirty years ago, Ralf Hotchkiss, an engineer with paraplegia and a frequent traveler to developing countries, saw the need for a high quality and rugged chair that could withstand conditions in rough terrain. He began a thirty year process of collaborative design using locally available parts with a cost low enough to be affordable to disabled persons in developing regions. For many years, Ralf and a team would travel to small machine shops in developing countries to teach the technical skills necessary for local production of the RoughRider model. Several of these shops are developing to scale in parts of Africa, Asia, Latin America and the former Soviet Union.