copied from here (too lazy to write it up again).

Quote Originally Posted by mclane View Post
While you are onto something, I think I beat you to it. I believe I've completed Tcaudillg's dual type theory (but I haven't still quite pinned down all the specifics). People have three types in total (it's actually four, but the fourth is kind of mystical -- it belongs to the soul). It is very similar to the enneagram tritype theory. The first dual type is going to invariably be supervisee or beneficiary (so as a LII, it would be either IEE or SLI). This one would belong to the head. The second dual type will be benefactor or supervisor (in the case of LII, IEI or SLE). This one would belong to the gut. Whatever club you have in the first passes on to the second (so if you are a LII-IEE, then you must be LII-IEE-IEI). Dual types also have subtypes in the two-subtype theory just as the main type. Also, subtype switches around for the second type (if one is producing the other one has to be accepting and so on). So in the case of LII, it gives these possible combinations:

1. LII-Ti - IEE-Ne - IEI-Fe
2. LII-Ti - IEE-Fi - IEI-Ni
3. LII-Ti - SLI-Si - SLE-Ti
4. LII-Ti - SLI-Te - SLE-Se
5. LII-Ne - IEE-Ne - IEI-Fe
6. LII-Ne - IEE-Fi - IEI-Ni
7. LII-Ne - SLI-Si - SLE-Ti
8. LII-Ne - SLI-Te - SLE-Se

This certainly would give more flavour to the possible types a person can be, and also explains the differences between people of the same type. If you add the "soul type" to these, it gives even more combination to a total of 16 (this number again?) per main type. So, doing the math, people would fall in total in a possible combined type out of 256 possiblities.
Let me know what you think of this theory.