Once a stopper is found with an end that fits snuggly in the mouth of the plastic bottle, the motor's shaft can be pushed into the center of the cork at the other end of the stopper. After adhering the two patterns to compact discs, cork stoppers of appropriate end diameter should be inserted in the holes at the center of the discs. As before, push the shafts of the motors into the center of the other end of the stoppers. [Extracted from the article]