Photocomix's Wild Cartoonizer filter gives 2 layers.
Why?

Since it was his only GMIC filter that created a duplicate layer, we may never know why PC added this option. I know that he utilized duplicate layers for his arrays/mirrors experiments, since he liked to clash different psychedelic layer orientations against one another into patchworks. AFAIK none of those experiments were hard coded to leave duplicate layers. Some of his artwork/resources can be seen at https://www.deviantart.com/photocomix-resources/t and his Flickr is at https://www.flickr.com/photos/photocomix-mandala/

Photocomix G'MIC code is here.

I can get rid of doubling layers by adding this before the second last line of the Wild Cartoonizer filter.


PS. I'm just a newbie at G'MIC code but I learned how to make my own filter code entry in G'MIC where I can play around with the filters.

I tested on 90 layers and then added Photocomix Psychedelic Glasswork Tiler.

Great outcome Tas! well done

Thanx for the like akky.

I experimented with SamJ's Skeletik filter on a landscape background. This is the GIF result.

so finally no solution for the levels 0 like me ... but no one died

Making your own filter is easy. I found instructions here.

My filter only has 1 line:
#@gui My first filter: my_first_filter_command, my_first_filter_command_preview
and below I pasted the whole Wild Cartoonizer code from here.

Photocomix made that easy because his filters are so well separated. Then do the mod I found and you have just one layer output.

Thanks very much Tas_mania. I'll try.