fold is cool!!

Ok, I was just learning erlang sintax.. Do you like my new solutions?

So reject it

Ja, you are right. Exepct that the recursion limit in more dependant in the Mechine's capacity than in the language.

Ok, thanks. Well, in my understanding (I'd appreciate you to correct me if I'm wrong), stack overflow may happen in case there is a great amount of recursions (depending on the language). Here, given the max value for an u64, there cannot be more than 20 recursions, so no way to get SO... Or am I wrong?

If you call a method recursively as you have done here, the call will evetually overflow the stack, so in languges like Haskell there is a optimization called Tail-Call optimization that in the background compiles the recursion to a more performant loop instead a recursion, this optimization just works in languages that implement it and just it the call is in the end of the method.

I dont't know what it is (I've just searched for it, and I can't figure it out...), and how this is related my solution. You'd be kind to tell me more :)

Rust don't have tail call optimization.

You should STUDY MATHEMATICS.

Also character arrays are zero indexed.

Because not all walks are of 10 length. Not a kata issue!

I don't understand what my code fails

That's not a kata issue. There's over 900 haskell completions. The code you posted clearly has syntax errors, and probably some logical ones too.

It should be at least 11 * 11.