I couldn't find the answer quickly enough. But I thought it was a cool tool.
Then I decided to search an old picture from flickr on a whim and lo-and-behold, I stumble upon it being used in an Irish architectural blog. Isn't that cool?
When I discovered it, there was no attribution, but after I sent an email, they responded promptly and cited my flickr :). I had posted it on flickr many years ago with a Attribution-Noncommercial-ShareAlike license.
Here is a snapshot of both on same screen.
|Leaf imprint in concrete, near Deike building, Penn State Main Campus.|
This post was updated on Sep 24, 2015.