Articles such as compact discs or electronic files are traded among a plurality of members who are registered in a common community. A compensation signal transmitted on the compensation signal line may be the inverse of a scan signal transmitted on a scan line. The training apparatus also includes a rigid panel for strengthening and supporting the reflective panel. The connector bolt allows users of the sanding apparatus to move the oscillating member up and down so that different size runs and drips can be removed from the paint without damaging the surrounding areas of the paint.