a small market for used machines still exists. As for the magnification-and-reduction feature of a pantograph (with the scale determined by the adjustable arm lengths), it is achieved in CNC via mathematic calculations that the computer applies to the program information practically instantaneously. Scaling functions (as well as mirroring functions) are built into languages such as G-code. Other uses Perhaps the pantograph that is most familiar to the general public is the extension arm of an adjustable wall-mounted mirror. In another application similar to drafting, the pantograph is incorporated into a pantograph engraving machine with a revolving cutter instead of a pen, and a tray at the pointer end to fix precut lettered plates (referred to as 'copy'), which the pointer follows and thus the cutter, via the pantograph, reproduces the 'copy' at a ratio to which the pantograph arms have been set. The typical range of ratio is Maximum 1:1 Minimum 50:1 (reduction) In this way machinists can neatly and accurately engrave numbers and letters onto a part. Pantographs are no longer commonly used in modern engraving, with computerized laser and rotary engraving taking favor. The device which maintains electrical contact with the contact wire and transfers power from the wire to the traction unit, used in electric locomotives and trams, is also called a "pantograph". Some types of trains on the New York City Subway use end pantograph gates (which, to avoid interference, compress under spring pressure around curves while the train is en route) to prevent passengers on station platforms from falling into or riding in the gaps between the cars. Some commercial vehicles have windscreen wipers on pantographs to allow the blade to cover more of the windscreen on each wipe. Old-style 'baby gates' used a 2-dimensional pantograph mechanism (in a similar style to pantograph gates on subway cars) as a means of keeping toddlers away from stairways. The openings in these gates are too large to meet modern baby gate safety standards. Herman Hollerith's "Keyboard punch" used for the 1890 U.S. Census was a pantograph design and sometimes referred to as "The Pantograph Punch". An early 19th-century device employing this mechanism is the polygraph, which produces a duplicate of a letter as the original is written. In churches in many countries (generally before modern animal welfare), dog whippers used 'dog tongs' with a pantograph mechanism to control dogs at a distance. Fools in German carnivals