Add to ORKGTangible Windows are a novel concept for interacting with vir-tual 3D information spaces in a workbench-like multi-display environment. They allow for performing common 3D interac-tion tasks in a more accessible manner by combining principles of tangible interaction, head-coupled perspective, and multi-touch techniques. Tangible Windows unify the interaction and representation space in a single device. They either act as physical peepholes into a virtual 3D world or as physical containers for parts of that world and are well-suited for the collaborative exploration and manipulation of such informa-tion spaces. One important feature of Tangible Windows is that the use of obtrusive hardware, such as HMDs, is strictly avoided. Instead, lightwe...