We're going to start with something easy. Something minimal. In fact, let's aim for the most minimal we can get.
Beware of the Turing tar-pit in which everything is possible but nothing of interest is easy. - Alan Perlis (Epigrams on Programming, 1982)
Beware of? No, embrace!
A Turing Tarpit is a type of esoteric programming language. It is Turing-complete but has a very small number of primitives (generally between 2 to 8 operations). This means we could use it to write any computable program but it definitely wouldn't be practical.
A common implementation uses cells as memory, like a traditional Turing machine. Cells can make up a tape or grid and instructions are given to move the cursor and set values.
This theme is very open-ended. Go on and write a Turing Tarpit!
Does this language introduce you to any new concepts? Does this seem like a unique language?
Does the implementation of this language work as intended? Does it lack many bugs?
Does the language fit the theme? Does it satisfy the constraints in the description?