The document discusses different types of interactions between humans, machines, and atoms. It notes that while humans interact with machines primarily through fingers and hands, interactions with other humans and the real world are often multimodal in nature. It also observes that machines currently provide information to humans in mostly one-directional and primitive ways, but that interactions could be improved, such as through nursing care robots. The document envisions opportunities for more amazing multimodal interactions if human effectors like voice, gaze, or brain state could be linked to machines to act on atoms.