Skew pantograph

Pantograph \Pan"to*graph\, n. [Panto- + -graph: cf. F.
   pantographe.]
   An instrument for copying plans, maps, and other drawings, on
   the same, or on a reduced or an enlarged, scale. [Written
   also {pantagraph}, and incorrectly {pentagraph}.]
   [1913 Webster]

   2. An electrical conducting device consisting of a
      collapsible frame resembling a pantograph[1], connected to
      the top of an electrically-powered vehicle such as a
      trolley, and used to conduct electrical current between
      the vehicle and an overhead electric wire, which supplies
      the power to the vehicle. The variable height of the
      pantograph ensures that it can move to follow variations
      in the height of the overhead wires, and thus make
      constant contact with the wires.
      [PJC]

   {Skew pantograph}, a kind of pantograph for drawing a copy
      which is inclined with respect to the original figure; --
      also called {plagiograph}.
      [1913 Webster] Pantographic