I just found this question on google and it looks like none of the answers here tell the full story. Please help.

The use of the word “pearl” here is a take on a type of paper in the Functional Programming community called “Functional Pearl”, a concept that was started in the Journal of Functional Programming and was based on the original programing pearls series in the Communications of the ACM published. In that original series the word Pearl was chosen to reflect that these “Pearls” were solutions that had been polished over time into particularly elegant programming solutions (as Joe McMahon conjectured). The series programming pearls was also published in books.

As described here and also on the ICFP website, a Functional Pearl should be elegant, fun and instructive.

This meme is often used with a twist (mostly in the programming language community). Here they have a “Educational Pearl”, I’ve seen a “Declarative Pearl” and a “Field Pearl”. Is this “functional pearl” on the design side, but has a different style?