Blocky saysConsensus is how independent nodes agree on the one true ordering of transactions.
With no central authority and a global network, who decides which block comes next? Consensus mechanisms are the rules that let nodes agree — and make cheating expensive. They solve the double-spend problem (you can't spend the same coin twice) by establishing a single canonical history everyone converges on. Proof of Work and Proof of Stake are the two dominant approaches.
Power-ups you unlock
Agree on one canonical transaction order
No central authority decides
Prevents double-spending
PoW and PoS are the main mechanisms
Double-Spend Dan attacks — common mistakes
Assuming consensus is instant/perfect
Ignoring the economic incentives behind it
Thinking all chains use the same mechanism
Boss battleExplain what problem consensus solves that a normal database doesn’t face.
Example code
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<body style="background:#06040d;color:#e6e0ff;font-family:monospace;padding:20px"><pre>problem: many nodes, no boss, who picks the next block?
consensus: rules that make agreement cheap and cheating costly
→ one canonical history, no double-spend</pre></body></html>