In this paper, we present a case study that explores how children could learn to interact with programmable matter. Flying drone swarms enable physical visualizations of complex data and simulation of physical objects and processes, e.g., planetary movements. The swarms can be digitally controlled as an ensemble as a form of (sparse) "programmable matter." We worked with the toy company LEGO®, to design and evaluate a "build and fly" experience with 240 children in a public exhibition. The children decorated a bendable handheld controller with LEGO® bricks and then used this controller to animate the flight of a 10-drone swarm. Results indicate that children enjoyed the constructive play and performance aspects of the system. Four main patterns of player behavior emerged, which we discuss in relation to possible improvements to the system. We provide implications for design of programmable matter systems for supporting child play experiences.

LightBee is a novel "hologrammatic" telepresence system featuring a self-levitating light field display. It consists of a drone that flies a projection of a remote user's head through 3D space. The movements of the drone are controlled by the remote user's head movements, offering unique support for non-verbal cues, especially physical proxemics. The light field display is created by a retro-reflective sheet that is mounted on the cylindrical quadcopter. 45 smart projectors, one per 1.3 degrees, are mounted in a ring, each projecting a video stream rendered from a unique perspective onto the retroreflector. This creates a light field that naturally provides motion parallax and stereoscopy without requiring any headset nor stereo glasses. LightBee allows multiple local users to experience their own unique and correct perspective of the remote user's head. The system is currently one-directional: 2 small cameras mounted on the drone allow the remote user to observe the local scene.

We present GridDrones, a self-levitating programmable matter platform that can be used for representing 2.5D voxel grid relief maps capable of rendering unsupported structures and 3D transformations. GridDrones consists of cube-shaped nanocopters that can be placed in a volumetric 1xnxn mid-air grid, which is demonstrated here with 15 voxels. The number of voxels and scale is only limited by the size of the room and budget. Grid deformations can be applied interactively to this voxel lattice by manually selecting a set of voxels, then assigning a continuous topological relationship between voxel sets that determines how voxels move in relation to each other and manually drawing out selected voxels from the lattice structure. Using this simple technique, it is possible to create unsupported structures that can be translated and oriented freely in 3D. Shape transformations can also be recorded to allow for simple physical shape morphing animations. This work extends previous work on selection and editing techniques for 3D user interfaces.

We present BitDrones, a toolbox for building interactive real reality 3D displays that use nano-quadcopters as self-levitating tangible building blocks. Our prototype is a first step towards interactive self-levitating programmable matter, in which the user interface is represented using Catomic structures. We discuss three types of BitDrones: PixelDrones, equipped with an RGB LED and a small OLED display; ShapeDrones, augmented with an acrylic mesh spun over a 3D printed frame in a larger geometric shape; and DisplayDrones, fitted with a thin-film 720p touchscreen. We present a number of unimanual and bimanual input techniques, including touch, drag, throw and resize of individual drones and compound models, as well as user interface elements such as self-levitating cone trees, 3D canvases and alert boxes. We describe application scenarios and depict future directions towards creating high-resolution self-levitating programmable matter.