Blockchain icon (Oracle)

Since I had developed key art for Oracle's Artificial Intelligence (click
here for full story) I was asked to develop a set of icons to represent the emerging technologies that Oracle was bringing to the market. 
The hardest part of the project was having to make the new icons encapsulate the very complex technologies they represented and still work at a tiny size. On top of that, he new icons also had to match Oracle's existing icon collection (see examples below).
What is Blockchain: A digital ledger or continuously growing list of records, called blocks, which are linked and secured using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp and transaction data. These blocks form a chronological sequence called a chain. By design, a blockchain is inherently resistant to modification of the data.
As always I started with lots of my microsketches:
I started off by trying to show the the lattice like structure of how Blockchain works
Next I tried to make the concepts less abstract and more depictive of blocks with a chainlike connection.
The concept of connected blocks was streamlined and the color contrast reduced to look less distracting and more 3D.
Some of the early ideas that I liked made larger:
Some slight refinements followed for the chosen concept:
Final icons
Emerging Tech icon suite