This paper presents Fluxa, a compact wearable device that exploits body movements, as well as the visual effects of persistence of vision (POV), to generate mid-air displays on and around the body. When the user moves his/her limb, Fluxa displays a pattern that, due to retinal afterimage, can be perceived by the surrounding people. We envision Fluxa as a wearable display to foster social interactions. It can be used to enhance existing social gestures such as hand-waving to get attention, as a communicative tool that displays the speed and distance covered by joggers, and as a self-expression device that generates images while dancing. We discuss the advantages of Fluxa: a display size that could be much larger than the device itself, a semi-transparent display that allows users and others to see though it and promotes social interaction.