The space-cadet keyboard is a keyboard designed by John L. Kulp in 1978 and used on Lisp machines at Massachusetts Institute of Technology (MIT),https://raw.

A now-legendary device used on MIT Lisp machines, which inspired several still-current jargon terms and influenced the design of Emacs. It was equipped with no fewer than *seven* shift keys: four keys for bucky bits ("control", "meta", "hyper", and "super") and three like regular shift keys, called "shift", "top", and "front". Many keys had three symbols on them: a letter and a symbol on the top, and a Greek letter on the front. For example, the "L" key had an "L" and a two-way arrow on the top, and the Greek letter lambda on the front. By pressing this key with the right hand while playing an appropriate "chord" with the left hand on the shift keys, you could get the following results: L lowercase l shift-L uppercase L front-L lowercase lambda front-shift-L uppercase lambda top-L two-way arrow (front and shift are ignored) And of course each of these might also be typed with any combination of the control, meta, hyper, and super keys. On this keyboard, you could type over 8000 different characters! This allowed the user to type very complicated mathematical text, and also to have thousands of single-character commands at his disposal. Many hackers were actually willing to memorise the command meanings of that many characters if it reduced typing time (this attitude obviously shaped the interface of Emacs). Other hackers, however, thought that many bucky bits was overkill, and objected that such a keyboard can require three or four hands to operate. See cokebottle, double bucky, meta bit, {quadruple bucky}. Note: early versions of this entry incorrectly identified the space-cadet keyboard with the "Knight keyboard". Though both were designed by Tom Knight, the latter term was properly applied only to a keyboard used for ITS on the PDP-10 and modelled on the Stanford keyboard (as described under {bucky bits}). The true space-cadet keyboard evolved from the Knight keyboard. [Jargon File] (1994-12-05)

Tom Corbett is the main character in a series of Tom Corbett—Space Cadet stories that were depicted in television, radio, books, comic books, comic strips, and other media in the 1950s.

Cadet is an unincorporated community in Union Township in eastern Washington County, Missouri, United States.

Air-head, ditz. One who is in a state of constant forgetfulness, or loses track of time.
Typically a person who is spaced out.
Where did I put my keys again? I'm a total space cadet. OR Jess, snap out of it. You're being a space cadet.

Space Cadet is a 1948 science fiction novel by Robert A. Heinlein about Matt Dodson, who joins the Interplanetary Patrol to help preserve peace in the Solar System.

Cadet grey (sometimes spelled cadet gray in parts of the United States) is a somewhat blue-greyish shade of the color grey. The first recorded use of cadet grey as a color name in English was in 1912.

The Interstate Cadet was an American two-seat tandem, high wing, single-engine monoplane light aircraft. Around 320 of these aircraft were produced between the years 1941 and 1942 by the Interstate Aircraft and Engineering Corporation based in El Segundo, California.

The Avro Cadet is a single-engined British biplane trainer designed and built by Avro in the 1930s as a smaller development of the Avro Tutor for civil use.