Comment by mpetrovich

At NextBigSound.com, we've found that a nestable fractional-based grid is generally easier, faster, and more flexible to work with than traditional N-column grids:

    <div class="grid--1/2 grid--2/3@M">
        <div class="grid--1/3"></div>
        <div class="grid--1/3"></div>
        <div class="grid--1/3"></div>
    </div>
    <div class="grid--1/2 grid--1/3@M"></div>