Four pillars of Bitcoin:

Ledger, mechanism, risk, reward.

1. Ledger (Blockchain) - Distributed, decentralised, synchronised database.

2. Mechanism (Proof-of-work) - Open-source, decentralised, cryptographic consensus algorithm.

3. Risk (Difficulty) - Thermodynamic requirement for the extrinsic commitment of energy, providing computational immutability.

4. Reward (Bitcoin) - Native, intrinsic asset, rewarded during game-theoretical competition.

Would anyone add, remove, or change anything here?