The Droste Style was set to Spikey Spiral to produce this
picture. It was based upon a photo of tree branches taken in my back
yard. Some of the branches crossed each other to form a roughly diamond
shaped area near the center, and that region was made transparent by using the
GIMP graphics program. The Droste Tool uses the transparent
area to determine which parts of the image should be replicated and where.
With a 'normal' Droste effect (see below), the recursions wind into the
transparent portion. The Spikey Spiral essentially unwinds the
framed area and coils it into distant nothingness.
The picture below was made from the same source image, but with the Droste
set to Winding Boxes
, creating a more traditional looking
effect. And here's a more colorful version of the above