Sir , you didn't get the subject matter here.. As I think I have difficulty in explaining. Maybe someone else can do it better. I apologize .
Parallel lines when it is with equal spacing. Imgur: The most awesome images on the Internet
A bottle and a cap for it are designed properly but what happens when you screw the cap on the bottle improperly. Yes cap is there but it's not aligned.. that's why in bottling industry a machine checks for cap fitment. And in car industry a gap Guage
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