Creating Wormholes

 

Easy enough to create these using the GIMP, Pan to Bow Script-fu, and Mathmap plugin. 

 

First, start with your target source (which I tiled 2X2):

 

 

 

Next, tile the source 4 times wider then height and also resize canvas to twice as high with embedded alpha channel:

 

 

Note the gap between the image and the following steps; it's because the image above has a transparent bottom.

 

Now run Pan and Bow:

 

 

Below's the Pan and Bow result:

 

 

Now run Mathmap's Droste preset; not the colored arrows which need to be played with or toggled.

 

 

You are done.  Result below:

 

 

Some additional tricks to try is to add more concentric circles within the larger circle as created by Pan & Bow (i.e., after Pan & Bow step, dup, and shrink the circular result to fit inside the larger circle).   Just experiment and have fun.   :)