I was going to look into it but never did. Oops. Oh well, guess I can try to find something unique, might make them the same species but I'm unsure yet.

I have a couple of twins, both are the same species, but different colors. (the boys) are not born on the same day, eventually that is explained in their story, but right now they are blank. they are one day off dec 12 and dec 13. same year, they are identical twins, but eventually Chev's hair lightens just enough to tell them apart in the light. My older set is boy/girl twins, they are different colors and species but with the same birthday. They are not identical twins at all.

I thought of experiment :

Faber's suggestion is actually what I immediately thought of as well since it's reminiscent of conjoined twins.

You could also do a opposite but same species idea, good vs. evil thing: i.e. the angelic/spectrum version of one species, the darkmatter/bloodred/blacklight/dark matter version of that same species as the opposite.

For what it's worth, my twin sets have always been the same species but different colors.

There are a lot of complimentary colors: spectrum/blacklight and harvest/glade come immediately to mind, but you also have the basic colors and you can go on the good vs. evil angle, such as angelic vs. bloodred/nightmare/darkmatter.

My current set of twins are angelic and glade keetos. That may seem like an odd pairing, but their poses are very similar - just flipped - and the coloring worked perfectly for their stories. I also used to have twins that were harvest and nostalgic jollins - another unusual pairing, but they both looked foxlike and still resembled each other a little bit.

Dawn and dusk (or twilight) colored pets would make for interesting twins.

(And now I want a set of blob triplets who are dawn, dusk, and twilight XD)

My twins are different species but same color, but both will get overlays to show better they are twins (both will get a German Shep overlay only in different poses). Both look pretty similar and only some really small details someone who knows them makes it easier to tell them appart (they are human OCs).

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