So, we all agree that every fusion has a different NUMBER extra features based on their compatibility, but what if the type of extra feature was based on their personality?

Opal:

Opal is seen with two eyes, two legs, and four arms. Pearl and Amethyst view the world similarly but act on their view differently, hence the combination of their four eyes into two, and keeping their four arms.





Garnet:

Ruby and Sapphire see the world the same way, but have a different perspective: Ruby more cynical, Sapphire more optimistic. This makes them meet in the middle to be a realist and have accurate vision of the future.





Sugilite:

Garnet keeps her third eye and gains two more in the fusion of Sugilite since she and Amethyst see the world differently. They also handle situations differently, giving Sugilite four arms.





Malachite:

Probably the most difficult is Malachite. She keeps her two normal arms since both Jasper and Lapis act with anger when they want something. Four eyes for different world views. But where about the foot-hand things?

I would love to here responses to this. :)