I understand "fast fart er 80" and it makes sense, but I think present tense "er" for mutable variables is super weird, and implies functional semantics in an imperative world. Like eg this:

    endreleg fart er 80

This is weird! It can change but it is 80? Was it already? Will it forever? Should that maybe be "blir" instead? (pardon my nonexisting Nynorsk, I'm extrapolanorsking from Danish "bliver") Eg:

    endrelig fart blir 80

So that later it can become a different value, eg

    fart blir 90

And the imperative nature of this bit of code is immediately clear to the reader.