He did not draw the skin incision to be made with the sterile marking pen the way the other professors did.

NEWYORKER: Personal Best

Using an easel and a marking pen to illustrate his point, Gingrich said the Republican plan actually called for substantial increases in those two programs.

CNN: Voters can decide thorniest issues, he says

First, acquire some sort of marking device: pen, pencil, charcoal or gouging stick.

FORBES: The How-To-Do Anything Guide