The engine contains no display, touch, network, or storage implementation.
Clients submit commands. The engine validates them and emits events.
Numbers, Letters, and Conundrum are independent modules behind one shared interface.
Only the current host commits authoritative state changes.
The score leader becomes host between rounds. Ties retain the current host.
Clock and random sources are interfaces to support deterministic tests.
Accepted events can reproduce match state and support debugging, recovery, and audit.
Conundrum word-and-hint packs may use a license separate from the engine.