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This is just using the framework that I made for the exercise. The students didn't have to do any Crazy IO stuff. You can see the parts under "Aufgabe" here, which is what they were supposed to code: https://github.com/def-/gifstream/blob/master/SnakeFinished....

Exercises in German here: https://github.com/def-/gifstream/blob/master/Aufgabe.pdf

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This seems interesting. Maybe I can use something similar next year to generate some interest. Without IO (which is monads, which is too advances since we also do functional C# and functional java paradigms in the same course) the subject matter is always a bit dry since the students have nothing but the ghci repl to get any interaction or feedback going.

What if you were to give students some functions like

    imShow :: [[Int]] -> IO ()
    playSound [Int] -> IO ()

? This would give them a little more liveliness but wouldn't require them to understand anything beyond "IO () is something that the repl can run". If they're feeling exploratory, maybe give them a few monadic combinators like >> to play around with, possibly specialized to IO.

You could also build a "sandbox" monad specifically for the class/framework. Let the students treat the monad as a blackbox Turing machine/state machine, unless they get time/interest/show aptitude to dive deeper. Doing that gives you the benefit that they don't accidentally google "Haskell IO" and fall down the monad rabbit hole without some preparation.

The most fun exercise for me was generating music in Haskell, but it was quite challenging and I remember not many students tried it.

https://code.world/

I wonder whether you can even hide the IO in the logic function by providing a random number from the outside which the students can use, so that from their perspective the logic function is pure, which would be quite desirable.

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