I learned APL in the mid 70's in college but never got to use it for much (I do remember writing a table tennis game which was pretty bizarre). But I always remember how amazing it was to learn the "combos" that did so much work in so few symbols. It was like learning to master a video game like Street Fighter. But APL was always a mostly write-only language, unless you used it every day, your code quickly became WTF-is-that.