An apparatus for indicating the position of a point detector bar having an outer surface and linked to a moveable point associated with a fixed rail utilizing a probe. The method includes the steps of: obtaining data representing the pattern; defining a plurality of distinct zones based on the critical dimensions of the plurality of features; categorizing each of the features into one of the plurality of distinct zones; and modifying the mask pattern for each feature categorized into a predefined distinct zone of the plurality of distinct zones. The vibratory plow assembly has a linkage assembly to connect to the power unit. In at least one embodiment, the marker comprises a chemical signature that is unique to a particular entity and is affixed to items authentic to that entity. This way, for example, when the clamp is engaged with the prong, it extends over and cooperates to hold a rifle sling on the middle region of the base beneath the clamp. The reduction gear system comprises a multi-stage toothed gear transmission with a toothed wheel on the drive input side, and the control drive comprises two servomotors which drive the toothed wheel simultaneously but whose driving action are slightly opposed to one another.