In this video I explain smart contracts. I start by explaining how they fit into, and interact with, the world state. I also explain how account and contract addresses are derived. Then I talk about bytecode and function selectors. I also touch on contract constructors and the ABI. Then I talk about function visibility and contract storage. Finally I explain Turing-completeness and why this feature is so important for smart contracs, and why Turing-completeness is essential to the World Computer vision.