The AN Plotter

When I was in the military occasionally we'd get training on different areas related to our job. For this training session we were going to deal with charting, we had to know all the different map projection types and how to use tools to write locations on maps.

As the instructor was preparing to start the course he found that most of the AN Plotters were broken. We called these AN Plotters (Air Navigational Plotters) pregnant rulers too, here's an example:
In his frustration he picked up one of the plotters that wasn't broken and started shaking it like a baton in time with what he said next. "I can't understand why all these plotters are broken!" Right as he said the word "broken," right in rhythm with the second syllable as he shook this plotter came a loud *SNAP*. The thing broke in two.

He looked in bemused dismay at the remaining half of the plotter that was in his hand having answered his own question as we all completely lost it.