To solve a problem about 23 years ago I wrote a programming language + interpreter. It was meant to be a simple language to write phone surveys in, so basically

To solve a problem about 23 years ago I wrote a programming language + interpreter. It was meant to be a simple language to write phone surveys in, so basically a kind of DSL for a single purpose. The programmers who built the survey taking system that would use my language discovered they could write much of it in the language itself, which surprised me a lot. Was a really fun project. No idea what happened to it.