Modern machining requires geometry & trigonometry & stuff. You may be familiar with graph paper and the X axis and the Y axis. To make parts, machinists have to know where the significant points are. Those points have to be calculated.
Above pictured (center) is the Rod's Duck Farm branding iron. To make the branding iron, a logo must be drawn. Then the significant points are calculated (ie., start and end point of line segments). Then a computerized router moves a cutting tool, according to the mathematically determined points.
The pencil is mightier than the sword .... that's why the core of the pencil is "graph-fight".