This is only just slightly related, but I am working on a project based on Algorand, and one of the interesting things about it is that the smart contracts are

This is only just slightly related, but I am working on a project based on Algorand, and one of the interesting things about it is that the smart contracts are written in something somewhat like an assembly language. It actually is deliberately not Turing complete because it does not allow looping or recursion, but has a few interesting features and constraints. For example, it has built-in cryptography instructions. The need to execute as many "programs" as possible to have a high transaction rate has pushed the design towards these intriguing constraints.