What does a ruler mean?

It is a tool for drawing line segments (especially straight lines) and measuring length.

Rulers used in different occasions have different requirements and standards. If more accurate values are required, then higher technology is needed, and they must be produced by machines. Besides the accuracy of numerical value, the second key point is the quality of engraving value. Generally, a protective film will be branded after the value is engraved.

One of Lu Ban's inventions is that he can correctly draw a right triangle, also called a class ruler, and can tell craftsmen which sizes are irregular and which ones are unlucky according to the rules of divination (geomantic omen). These rulers were bought today.

Extended data?

Daily protection of rulers:

1, ruler should not be mixed with knives or metal stationery, and be sure to cover the pen when mixed with it.

2, be sure to prevent exposure and long-term sun exposure, especially the plastic ruler has poor temperature resistance and will be deformed.

3, it is best not to brush clean, which means try not to dirty the ruler.

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