Columns and the Greatest Common Divisor

I was recently putting together some CSS for columns. There was a few pre-determined widths that the columns needed to accommodate. For whatever reason (maybe because every grid framework in the world is this way) my mind went right to trying to find a common building block size. All columns are either the size of one building block or a multiple of a building block with gutter widths added.

You know what I mean:

So I had this…

Columns and the Greatest Common Divisor is a post from CSS-Tricks