I learned APL on an IBM 2741 terminal[1], a terminal kind of like a teletype but with a Selectric typewriter attached to it for the keyboard and typing mechanis

I learned APL on an IBM 2741 terminal[1], a terminal kind of like a teletype but with a Selectric typewriter attached to it for the keyboard and typing mechanism. This APL360 system had APL particular and idiosyncratic symbols on each of the keys (in addition to the regular QWERTY keys). The shift key selected which symbol would be produced. This made learning APL a lot easier. The Selectric type ball was special and had the APL characters on it. Interestingly, the same kind of a system was available for ALGOL68 programming and provided symbols useful for that language. [1] https://en.wikipedia.org/wiki/IBM_2741 https://en.wikipedia.org/wiki/IBM_2741