I have no idea why you're confused. :D Does the concept of a recursive array make sense to you? A recursive(ly typed) function? Or do you think such things

I have no idea why you're confused. :D Does the concept of a recursive array make sense to you? A recursive(ly typed) function? Or do you think such things can't exist? Like "[[[], []], []]" could be an instance of "mu X.[X]" right? https://en.wikipedia.org/wiki/Recursive_data_type#Isorecursive_types https://en.wikipedia.org/wiki/Recursive_data_type#Isorecursi...