8. A method comprising: tracking a location of a pen instrument when the pen instrument is used to modify a physical document, wherein sensors within the pen instrument track the location of the pen instrument; generating signals describing movement of the pen instrument based on the location of the pen instrument; transmitting the signals to a receiving device, wherein the signals are used to modify an electronic document corresponding to the physical document, and further wherein strokes made with the pen instrument are displayed when the electronic document is displayed.
8. A method comprising: tracking a location of a pen instrument when the pen instrument is used to modify a physical document, wherein sensors within the pen instrument track the location of the pen instrument; generating signals describing movement of the pen instrument based on the location of the pen instrument; transmitting the signals to a receiving device, wherein the signals are used to modify an electronic document corresponding to the physical document, and further wherein strokes made with the pen instrument are displayed when the electronic document is displayed. 9. The method of claim 8 wherein generating electrical signals describing the series of strokes comprises generating the electrical signals with at least one transducer to sense self motion in a multi-dimensional space.