Genesis. The first block forms out of raw data. It has no parent: everything after it is built on top of it. The network of peers wakes around it. A transaction is signed with elliptic-curve cryptography and gossiped node to node. The chain itself is forged from 0s and 1s, one link hooked through the next. Today it lives on computers all over the world: a new block ripples out until every node has it, with no central server. In proof of work, miners race to find a hash below the target; the winner seals a block whose Merkle tree commits to every transaction inside it. Each block carries the hash of the one before, so the chain grows, and changing any block would break every link after it. At the end, blocks that fall off the bottom of the chain are kept alive by a two-robot crew: a drone lays a new stretch of electric highway, a robotic arm sets the block down at its end, and the connection goes live. Hash rates and hashes here are simulated.