Colorful carpet of leaves

I wanted to post an image from my autumn impressions today. I was experimenting of several occasions on panning with static subjects, and thought about posting such an abstract of colors characteristic for the season. And then I saw this image in the gallery and was so surprised. Take a careful look at the photo, because then you can start distinguishing the shapes of branches and leaves on it. Unfortunately, this effect was not achieve purposefully, so I cannot really tell how I did it :(. But from the look of it, I must have stopped camera movement too early and and some of the image recorded sharp.