Hey Moctezuma! Thanks for the many entries. I like (28,29,30) very simply style and effect! Like 26,27 less because it becomes too computer like, we don't want machine associations. Could you try to make versions with warmer and brighter colors, and some that are not necessarily a mix of blue and orange. For the 29,30 would also be interesting to see how they look if the colors shifted gradual from center to exterior. :)
Another thought is that 28+30 if stand alone the symbols will not be associated with a brain, can you play with shape, fx. elliptic so they would seem like brains