Bitcoin's code was open for anyone to copy — and many did. Namecoin appeared in April 2011, the first chain to fork from Bitcoin's code. In October 2011, Charlie Lee launched Litecoin, faster and lighter, calling it the silver to Bitcoin's gold.

Soon there were hundreds of chains, then thousands. Some were bold experiments, some were copies with a new name, and some were jokes. Each became a little kingdom, with its own rules, its own coin and its own loyal townsfolk.

In December 2013, two software engineers, Billy Markus and Jackson Palmer, made a coin as a joke. They named it Dogecoin, after a popular picture of a Shiba Inu dog surrounded by broken words: such wow.

The joke grew a warm heart. Its fans tipped one another for kind words online, and in 2014 they raised money to send the Jamaican bobsled team to the Winter Olympics in Sochi. Years later, famous voices on social media sent its price soaring. A reminder that people, not code alone, decide what a coin is worth.

Some builders chose speed. Solana, whose clock we met in Chapter IV, bet everything on one fast chain, with fees of a fraction of a cent and a new block every blink. It has raced ahead — and stumbled, halting more than once in its early years.

Others chose care. Cardano, led by Charles Hoskinson, a co-founder of Ethereum, launched in 2017 and built its proof-of-stake design from peer-reviewed research, adding smart contracts only in 2021. In Aesop's fable the tortoise wins. In blockchains, the race is still being run.

With so many kingdoms, travellers wanted to carry their coins from one to another. Builders dreamed of an internet of blockchains. Polkadot, founded by Gavin Wood, launched in 2020; the Cosmos network connected its chains in 2021 with a shared language called IBC.

Elsewhere, people built bridges: vaults that lock a coin on one chain and issue a copy on another. Great vaults attract great thieves. In 2022 alone, the Wormhole bridge lost about $320 million, and the Ronin bridge, behind the game Axie Infinity, lost over $600 million.

A blockchain is a sealed library: it knows everything written inside it, and nothing at all about the world outside. It cannot see the weather, the score of a match, or the price of gold. A smart contract that pays out when it rains needs someone to tell it that it rained.

Those messengers are called oracles. The best known, Chainlink, launched its network in 2019, gathering prices from many independent reporters so that no single liar can fool the contract. Oracles now feed the prices that lending markets, stablecoins and tokenized stocks rely on every second.