Description needs to add more explanations and examples to clarify when we are supposed to stop parsing the input string. For example in the second example of basic tests, it returns "BruuJ", "nothing on the bottom line, so parsing should end". However one could easily extend the result by continuing upright with "D", "H", etc., that is following the description ("The message ends when there is no space at the right up or down diagonal."). The same case could occur on the second diagonal if one line is shorter than others, so what are we supposed to do?