Shape-changing interfaces are physically tangible, interactive devices, surfaces or spaces which allow for rich, organic and novel experiences with computational devices. Over the last fifteen years, research has produced functional prototypes over many use-applications, and reviews have identified themes and possible future directions-but have not yet looked at possible design or application based research. Here we gather this information together to provide a reference for designers and researchers wishing to build upon existing prototyping work, using synthesis and discussion of existing shape-changing interface reviews and comprehensive analysis and classification of 84 shape-changing interfaces. Eight categories of prototype are identified, alongside recommendations for the field.