This is my first post to S\O and I'm trying to get my head around the following code and why it works so I can have a better understanding on how to implement my own code.

I'm going through the Odin Project and I'm stuck on creating a 16 x 16 grid. I choose to look at an example, but am unsure how it fully works.

Here's the code:

function createGrid(x) {
    for (var rows = 0; rows < x; rows++) {
        for (var columns = 0; columns < x; columns++) {
            $("#container").append("<div class='grid'></div>");
        };
    };
    $(".grid").width(640/x);
    $(".grid").height(640/x);
};

I don't understand why the bottom two lines are needed. I thought the loop would be enough to create the grid?

Thanks in advance.