You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: snail.rs
    path of file: ./repos/Rust/src/dynamic_programming
    
    the code of the file until where you have to start completion: /// ## Spiral Sorting
///
/// Given an n x m array, return the array elements arranged from outermost elements

    
    fn test_char() {
        let square = &[
            vec!['S', 'O', 'M'],
            vec!['E', 'T', 'H'],
            vec!['I', 'N', 'G'],
        ];
        assert_eq!(
            snail(square),
            vec!['S', 'O', 'M', 'H', 'G', 'N', 'I', 'E', 'T']
        );
    }