World
The base of every game's state: the world owns its entities and nodes as plain properties, advances through update, and is drawn as root.
Immediate-mode: the game declares its state as ordinary vals, vars, and lists — an entity moves by rebinding (ball *= motion), leaves a list by removal — and scene projects whatever currently exists into draw order. Nothing is registered with the engine and nothing is retained between reads: root is recomputed from scene on every read.