fn main() {
    let mut m: [[u8; 16]; 9] = [[0; 16]; 9];

    m = four(m);

    println!("{}", m[5][5]);
}


fn four(mut m: [[u8; 16]; 9]) -> [[u8; 16]; 9] {
    for i in 0..15 {
            m[i][5] = 4;
    }

    m
}