This document discusses non-textual interfaces for AI in smart environments, focusing on virtual (VR), augmented (AR) and mixed (MR) realities. It covers an overview of different realities, design guidelines for VR communication and different realities, perceptual models and modalities, and designing IoT for mixed realities. The key topics covered are definitions of VR, AR and MR; immersion and presence tradeoffs; input and output components of VR systems; and challenges of designing contextual interfaces that span multiple devices and realities.