Since the scale line of a general ruler has a width, many people have had the experience of trying to draw a line of the correct length with a ruler and wondering 'how far should I draw this scale ...

There are a lot of people who experienced the experience that the ruler was carelessly deviated when drawing a line with a ruler and the line rattled ..... So, we made a little effort on the rulers, ...

A social media post this week made thousands of people pick up the nearest ruler and look at it, really look at it, for what ...