Educational simplification: one topic with four partitions, up to three brokers, and a compact KRaft-style controller. Real deployments can contain many topics, partitions, racks, quotas, network links, and client libraries.
Production focus: watch how leader-only writes, follower replication, ISR, min ISR, consumer lag, and rebalances interact during overload and failure.
Visual invariant: every moving event follows the visible connector line and direction. When leaders or assignments change, routes and particles are rebuilt together.