In this paper, we explore how shape changing interfaces might be used to communicate emotions. We present two studies, one that investigates which shapes users might create with a 2D flexible surface, and one that studies the efficacy of the resulting shapes in conveying a set of basic emotions. Results suggest that shape parameters are correlated to the positive or negative character of an emotion, while parameters related to movement are correlated with arousal level. In several cases, symbolic shape expressions based on clear visual metaphors were used. Results from our second experiment suggest participants were able to recognize emotions given a shape with a good accuracy within 28% of the dimensions of the Circumplex Model. We conclude that shape and shape changes of a 2D flexible surface indeed appear able to convey emotions in a way that is worthy of future exploration.