The paper is accompanied by a ZIP archive containing the following files: The file “Manipulation-sequence.avi” contains the sequence of intermediate images recorded during the manipulation, the final result of which is shown in Figure 4. The file “3Dmovie.avi” contains an animation exhibiting the 3-D model of the recorded manipulation trajectories shown in Figure 3 (for details cf. the caption of Figure 3). The file “3Dmodel.html” contains an interactive 3-D model of the recorded manipulation trajectories. To be viewed it must be placed in the same directory as the file “CanvasMatrix.js” (included in the ZIP archive) and opened with a browser. Use the mouse to rotate or zoom the field of view of the 3-D model.