Here is a G'MIC preset to help automate the process described in AnMal's first tutorial, above.

This preset does NOT do the first step (generating an image using a conical gradient or some other means) nor does it do the last major step, the Whirl and Pinch (which is a Gimp plug-in).
But it does do the 5 steps in between, ie.
- Cartesian Transform
- Kaleidoscope
- Offset x/2,y/2
- Kaleidoscope (transparent) and merge
- Offset x/3, 2y/3

At each step, the parameters default to the same as used in AnMal's tutorial, but you can tweak those values to get a better result.
Also, each step has an "Enable" checkbox so that you can selectively disable steps or just turn them on progressively to check how the pattern develops.

Installation

To use this preset, do Select-All on the code-box below, then copy and paste the text into your personal gmic file:
On Linux: ~/.gmic
On Windows: C:\Users\user\AppData\Roaming\gmic
(Note that the filename begins with a dot on linux, but not on Windows!)
You will need a plain-text editor such as gedit (on linux) or notepad (on Windows) to edit the gmic file.



If you do not currently have a personal gmic file, just download the file attached below, unzip and copy to the relevant folder. (On Windows, rename the file without the leading dot!)



Usage
The next time you invoke G'MIC you should find the new preset under "Testing> AnMal".
(It's called "AnMal Pattern 1" because the output is not actually paisley-ish - that will only happen when you run Gimp's Whirl-and-Pinch plugin on the output image.)
If you're going to be playing with this a lot, make it a "fave" so you don't have to keep scrolling down to Testing.

Note that you can start with any image, not just the conical gradient pattern described in AnMal's tutorial.
Run the new preset first with default settings (click Reset if necessary), then run Gimp's Whirl+Pinch on the result.
If you kinda like the result but think it could be better, ctrl-z twice to get back to the starting image, run the G'MIC preset again but this time tweak the parameters in the various steps and try again.

Starting image:

(This image was made using white clouds brushes on a black background, then G'MIC Graphic Novel, G'MIC Dream Smoothing and Gimp ACE.)

A few more:

Jontait2 - thanks for the 'preset'; but this old guy cannot seem to get it to work and nothing shows up under GMIC>Testing>Anmal.

Steps I took were;
1. Download you 'personal' zip file
2. Unzipped the file and placed it in C:\Users\user\AppData\Roaming\gmic - just to be sure the last couple of statements were "-endif #@gimp <b>Testing</b>"
3. Copied the 'select all code' and pasted it via notepad directly below the last two statements above
4. Started GIMP & opened GMIC .... nothing under testing for Anmal.

Was that the correct way?

I normally keep all my GMIC files under 'user>user-name>gimp2.8>plug-ins'. Does that make any difference to your code?

I don't know quite what you've done there, OMG, but you don't need to download the zip file AND copy/paste the code - it's one or the other!

If you don't currently have a gmic file in your personal profile (because you've never used locally-stored presets before, as most people haven't), just download the .zip file, unzip and copy it to the relevant folder. On Windows you will have to rename the file from ".gmic" to "gmic" (ie. without the leading dot), but that's all! No copy/pasting. Just re-start G'MIC and you should find the new preset in the filters tree.

The only people who will need to copy/paste the code from the code-box shown above are people who have previously used locally-stored presets and who do still have a gmic file in their personal profile (and I guess they should know what they're doing!).

Jontait2 - thanks, revised my approach as per your instructions but still nothing appears in GMIC>Testing.

Let me just make sure that when you say 'relevant folder' you mean copy the file to folder Roaming i.e under C:\Users\username\AppData\Roaming?

Thanks for the preset jontait2. It's been a while since I added a preset this way, but it did work and it now shows up per your post. Still, can't seem to get a decent whirl/pinch result. Regardless, adding Mehdi's Kaleidoscope to the result (after whirl/pinch) gave this result.

Yes, correct (as far as I know).
I'm a bit stumped, OMG - Lyle seems to have got it to work okay.

Just rename .gmic to gmic (I run GIMP in Win8.1) and then place it in the directory as you said (not the gmic directory; the one where you said) and do refresh. Done. If you can just automate the whole process; that would be cool then. Thanks again jontait2.

OK; figured out a few more things; then applied rotational C/L to that result.

this is so cool! i've never ever had a g'mic preset named after me before - and neither has erisian, so now i can hit him over the head with that whenever he gets too cheeky .

in any case, thank you, jontait. this preset can save me quite a bit of work (if i get it to work, i've never installed a g'mic preset before), very helpful of you. you got some really nice looking patterns there too, especially i liked the one based on the cloud brush image.

lylejk: wow, you're the king of paisleys now! that last one is really amazing. but does this mean your back in your old addiction again?

here's my contribuiton to the trendsetting done by members of this site lately. we might get into the next issue of vogue if we hurry...

Cool stuff.

jontait: i'm a bit of an idiot with these things, really, so i couldn't get that preset installed. i won't pester you for help, but i do wonder: i'm running the latest downloadable windows version of gimp and g'mic, but i'm running them from xp. could this be a reason it doesn't work? if so, i won't put down any more work on installing the preset.

Yes. that would be an issue! (I didn't realise anyone was still using XP).
I think on XP the relevant folder is:
C:\Documents and Settings\<username>\Application Data\

NB. that folder is hidden by default, so if you are using the Windows Explorer to save the file, you may need to do:
Folder Options> View> Advanced settings> Hidden files and folders> Show hidden files and folders

jontait: ah, that means i can give it another go, but i'm not getting my hopes up - plenty of ways i could mess this up . thank you!

i hate being reduced to an antiquated laptop and an antiquated windows version!!!!!!! next time i can afford a new laptop i'll install a linux system.

Appreciate the feedback AnMal.

lylejk: you're welcome. so when will we see the endless field of whirl-and-pinch paisleys? you know that's what we all expect now!

OK Anmal; included the actual tile too. Glad GIMP still works after my Win10 upgrade. lol

lylejk: we're drowning in paisleys now - we got both the endless field and the maelstrom/whirlpool. nice job, brother.