use std::{
    convert::TryFrom,
    iter::Iterator
};

struct Coord(i32, i32);

impl<T> TryFrom<T> for Coord
where
    T: Iterator<Item=u8>
{
    type Error = ();
    fn try_from(bts: T) -> Result<Self, Self::Error> {
        Err(())
    }
}

fn main() {
    let mut it = [0, 0, 0, 0].iter();
}