The problem
Transmitted images are flat; the viewer loses all depth information about the object.
The innovation
A pair of concave mirrors that produce a real optical image appearing to occupy space in front of the display, transmissible to a remote location.
How it worked
A concave mirror forms a real image in front of itself; pairing the mirrors at transmitter and receiver reproduces the effect remotely.
Why it mattered
Assigned to NASA; explored for scientific visualisation and later cited in 3-D imaging work.
The legacy
Sits in the lineage of volumetric and free-space display research.
Sources
US Patent 4,229,761
Follow the invention
The Ishango Bone
A baboon fibula marked with three organised columns of tally notches, excavated by Jean de Heinzelin at Ishango on Lake Edward.
The manuscript libraries of Timbuktu
Hundreds of thousands of handwritten manuscripts, including works on astronomy and medicine, held in family and institutional libraries.
Foil-electret microphone
A polymer film holding a permanent electrostatic charge, removing the need for an external bias voltage.