The parts that make this work
Validators and the UNL
Anyone can run a validator, but running one doesn't give you influence. Influence comes from other people putting your validator on their Unique Node List. Most servers use a published default list of around 35 validators, run by universities, exchanges, and independent operators. Ripple runs one of them.
Why the threshold climbs
Starting at 50 % and ending at 80 % lets validators quickly discard transactions few peers have seen, without stalling on a single disagreement. Different servers can have slightly different UNLs and still converge, as long as the lists overlap enough. A transaction that misses one ledger is retried in the next.
Finality in seconds
Because a ledger only counts once 80 % of trusted validators have signed its hash, there's no waiting for confirmations to pile up. A payment that appears in a validated ledger is settled. Ledgers close every 3 to 5 seconds, and each one records the hash of the one before it.
What a transaction costs
The base fee is 10 drops, which is 0.00001 XRP. It's a spam deterrent, not a reward, and it's burned. When the network is busy the fee rises for everyone, which is what makes flooding the ledger expensive. Accounts also lock a small reserve of XRP to exist on the ledger.
What live mode shows
Live mode connects to a public XRP Ledger server over WebSocket and draws mainnet events as they arrive. Each violet dot is a real transaction the server has provisionally applied to its open ledger. The inner ring holds the validators on the default UNL published at vl.ripple.com; the outer ring fills with every other validator the server hears from. A beam means that validator has just signed the next ledger. The ledger numbers, hashes, transaction counts and burned fees are real. The server doesn't say which validator first received a transaction, so transactions fly straight into the open ledger.
What the animation simplifies
Real consensus runs continuously: validators keep exchanging proposals while the ledger is open, and "rounds" are timing windows rather than discrete steps. The counts and transaction volumes here are illustrative. Read the XRPL consensus documentation for the full protocol.