Ask HN: iPad app for prototyping ideas

I'm a mobile app and occasional web developer. Over the last few days, I have began setting my iPad up so I can do more work on it. The easy ones are thInge like planning and researching (reading docs). I'd like to prototype ideas. Mainly, bits of programs I am currently working on. I'm not prototyping UI. So I can simulate UI with logging. This can all be throwaway code. One of the reason I'm doing this is to use it as a drawing board, so I can hopefully be more efficient when I sit down and write the actual code. I'm handy with several languages so I'm flexible here. I am aware of Swift playgrounds, but I don't particularly like Swift and feel it's too complicated for my purposes. I have Blink. I would rather not need to connected for prototyping. Any suggestions?