A wiring pencil (often sold under the trade names of Roadrunner[1] or Verowire) is a tool for making electrical connections.
A small reel of insulated copper wire[2] is mounted at the top of the tool.
The wire runs down the center of the wiring pencil and through a hardened tip, which is small enough to move between the pins of 0.1" pitch DIL chip allowing connections to be wrapped and the wire to be led across the circuit board to the next point it's needed.
The wire is coated with a polymer lacquer (commonly referred to as enamel, but not glass based).
Once wrapped the connections are soldered, the heat of this burning the lacquer away and completing the joint.