Google's new world model, Dreamer 4, was trained purely through "imagination".

Google DeepMind has released Dreamer 4, a scalable agent that solves control tasks by training its imagination on a fast and accurate world model. It is the first agent to earn diamonds in Minecraft using only an offline dataset. Dreamer 4 leverages shortcut forcing objectives and an efficient Transformer architecture to accurately learn complex interactions, enabling real-time human-computer interaction and efficient imagination training.