In order to skim these very quickly in search of a particular target, it seemed essential to represent as many as possible at a time, i.e., to minimize the thumbnail size. Fortunately, prior research with images [8], still thumbnails [9] and moving thumbnails [10] suggests that humans are able to classify and recognize content even at very small sizes. Based on these results and informal testing, we concluded that representing 625 thumbnails on the screen of the target device, a Google Nexus tablet with a 9-inch screen, was sufficient for most cases (cf. Fig. 2a). For others, the option was added to enlarge the storyboard to 225 thumbnails per screen (cf. Fig. 2b).