I'd honestly say that writing a code generator to generate 1 million lines of code at random, and then analyze what it produces is probably the easier way to approach this - 1 million random lines of code have less potential variations than 100 billion neurons do, after all.
The variation in human brains is only a very small part of the potential variation in brains containing 100 billion neurons. I'm not saying we can engineer a million line program to grow a human brain, only that we'll never know whether it's possible unless someone actually does it.
Some people manage by the book, even though they don't know who wrote the book or even what book.