Adding to this, if you’re not scaling for area, a line/bar would make more sense. For this chart, the circle (scaled properly for area) seems like the right choice.

In manufacturing “operate” can mean a lot of things. For this machine, they probably mix the ingredients, add the mixed ingredients to this machine, clear jams or other faults, and clean the machine at the end of a run.

Depending on the factory they may also run different compositions or different shapes of pasta for different products. The operator would have to know which transitions need what level of cleaning, and they would clean and change the die.