We present Canvas Dance, a prototype of an interactive dance visualization for large-group interaction that targets non-professional dancers in informal environments such as parties or nightclubs, and uses the smartphones of the dancers as the input device for the motion signal. The visualization is composed of individual representations for each dancer, and the visual mappings designed for their dance moves have three main goals: to help the users identify their own representation, to uncover and inspire imitation among dancers, and to support unpredictable dance moves.