We stay away from riddles, and instead focus on CS concepts. We'll rephrase to avoid jargon if you don't have a formal education, or it has been a while. Here are a few categories:

• OOP concepts like SOLID
• concurrency vs parallelism, approaches for each (generators, threads, async,' etc), and tradeoffs
• typing (e.g. is a Python strongly or weakly typed? Java? JavaScript?), and practical implications
• functional programming concepts like closures, partial application, etc
• SQL knowledge
• types of tests, and approaches/goals for each

And some practical details like:

• major implementation details of our stack (Python's GIL, browser features like service workers, etc)
• git and docker experience
• build systems and other dev tools

That covers most of it. We don't expect every candidate to know everything, we just want to get an idea of the breadth and depth of their knowledge.