The Covenants Series

// The coins must flow

Part 1: Soft Forks
Part 2: Signature Hashes
Part 3: Covenants and Recursion
Part 4: OP_CAT

Output scripts control how coins are locked, not how they can be spent. If outputs scripts were extended with that power though, it sure seems to simplify a lot of offchain contract patterns. But understanding the concept of covenants requires a pretty solid grasp of Script, so have to wind it back a bit before talking about the possible future.