RotoSketch is an intuitive tool for sketching, doodling and notating on top of video, such that the marks made are linked in time with the video. This allows the user to draw strokes along the axis of time, as well as the normal x and y axes, and for those strokes to augment, analyze, interpret or even obliterate a video sequence. While usable in other contexts, the software tool has been designed specifically to be creatively useful in the process of dance making. This video was made during a development session during the 2006 Bank Project organised with choreographer Siobhan Davies. Original development by Zachary Lieberman, Scott deLahunta and Susan Rethorst with the support of Dance Theater Workshop (DTW) Research Fellowship 2004/05.