I actually created my own very basic blockchain tonight.. took me like 20 hours straight to get the foundation ready. I wrote it from scratch in Java, a PoW kind of blockchain.

I gotta say, your brain really gonna hurt when it comes to the networking (peer-to-peer) part.. that was a pain in the ass! That took like 70% of all my time to figure out. Now my blockchain can send coins, mine blocks, reset/resync the whole blockchain from another node-peer if it's invalid/broken etc.

But there's still ALOT left todo, believe me. I haven't figured out how to fix the Difficulty alghoritm yet.. I just made it fixed at Difficulty 4 at the moment.

I just did it for education purposes, I have another project in mind that actually don't involve cryptocurrency.. but it needs a blockchain to run on. So I started off small to get a grasp on how a blockchain actually work from the ground up. Im just amazed how the ethereum crew manage to do what they do..