A pixel art image of a mushroom

Quint

Quint is a formal methods language by the creators of the Apalache symbolic model checker for TLA+.

Quint is not a programming language , but an executable spec language. I believe the difference is the objective, a programming language main objective is computation, while an executable spec language main objective is verification.

Some languages like Agda, Liquid Haskell, etc blur the lines a bit.