APL is how non-programmers imagine what programming is, a kind of sorcery involving exotic symbols and elaborate ritual processes to create data and algorithms out of thin air. Like LISP, it's an eternal classic that every generation rediscovers and gets their mind blown as an educational experience about the strange nature of computing, logic, and language.

Notation as a Tool for Thought, the 1979 ACM Turing Award Lecture by Ken Iverson who developed APL, is insightful in understanding some of the thinking behind it.