The concept is dead simple: when the pencil is short enough to be a pain to use, plug the next pencil into it. This gives you the right leverage to keep using the pencil until it is truly gone. The sad thing is this is an invention that is at least 10 years too late, unless artists are willing to take the brunt of the increased costs from retooling pencil machines that have not changed in what? 100 years? That said the rest of the developing world is using pencils, and I am sure that using that last couple of inches of pencil is going to save so much that they should probably make these mandatory.