Here's my favourite example of a layout that to the best of my knowledge, you can't solve with flexbox. I've only been able to solve it with JavaScript<p>A grid representation of a list, let's say a list of image thumbnails along with small amount of other data. Something like the image grid in iPhoto.<p>What's so hard? Let me expand the requirements. I want the dimensions of each item to be identical, let's say a square. I also want each item to be as close to a specific size as possible, but scaled up or down slightly to allow each row of items to exactly fit the width of the containing element. With the exception of the last row, which is allowed to be unfilled.<p>You can <i>nearly</i> do this with flexbox. The only problem is that the elements in the last row will be stretched to fill the row if it's short a few items. It's also fairly awkward ensuring the height of an element matches it's width, the current solution seems to be a hack involving padding-bottom.<p>I'm planning on trying out <a href="http://gridstylesheets.org/" rel="nofollow">http://gridstylesheets.org/</a> to see if it's expressive enough for what I want. Of course, the catch is that I'm still depending on JavaScript.