I highly doubt this is how nature develops brain folds, but my Dremel was happy to participate.  Sadly, I went through three Dremels in the process of carving the cranium.  This is certainly usual - two of them were returned due to faulty wiring.  The final one was my gem and has worked overtime for me.  Despite that, this is the beginning of the brain taking shape.  Diamond cutting discs are a gem.  Expensive but a gem!  Eating through limestone like nobody's business.

Drawing the intricacies of the brain was the most rewarding point of the sculpture.  It was nice to see that the sculpture was beginning to resemble the concept of a brain.  There were a few changes and developments with the design - overall the organic concept transpired.  Take a look:

Took a while to work on the roughing the brain into a smooth state.  The outcome is positive and quite different from the initial roughing as per below.

Top Images - Initial shaping
Bottom Images - Machined shaping and smoothing