APL is an acronym for "A Programming Language". It was originally invented by Ken Iverson for use in mathematics, and was originally called 'Iverson notation'. It was published a few years later in a book bearing the language's current name.

it is one of the more unusual programming languages for 3 reasons:
1. Instructions are read from right to left.
2. it does not differentiate between single variables and arrays. to put this in C terms, [ 10, 9, 8, 7, 6 ] + [ 1, 2, 3 ] == [ 11, 11, 11, 7, 6 ] . or: 9 + [ 1, 1 ] == [ 10, 1 ].
3. It uses nonascii symbols for some of its functions. Thus, awkward input methods or special keyboards are required.

I would like to show an example, but I am uncertain how to show APL's special charachters in everything2; Unicode apparently has them, but does E2 support unicode?