The free pattern can be found here. Unfortunately I had several projects that had to come first so it stayed on the list for a LONG time. A few weeks ago I happened to walk down the clearance aisle at Walmart and discovered the variegated yarn in the pattern there. So I bought several skeins so they didn't run out before I had a chance to make this afghan. I rarely actually follow the exact colors used by the designers when I find a pattern I really like, but for this one this particular colorway really adds to the watercolor effect.
I made a few modifications but mainly followed the pattern pretty closely. One of the modifications I made was to add a chain-1 between the corner dc-clusters on round 2 of each granny square so I could join the granny squares as I went along and avoided a lot of sewing. I also used a size K crochet hook instead of L.
I'll definitely be making this afghan again, possibly in other color combinations.