Created in 1967 as an educational programming language that encouraged students to explore on their own, Logo is mostly remembered today for making turtle graphics popular. But it's much more than that; a Lisp for ordinary people, really, with hidden power few others can match.
I made three dialects of my own during the 2010s, exploring various facets of the language:
All of them proved broken in the end, and I abandoned this line of research.
Last but not least, LGO-40 is a turtle graphics calculator of my own design.