I found some teachers, like math, music and English teachers, they sometimes can't draw straight lines or shapes very well when they don't use rulers.
In addition, when teachers are drawing straight lines, they will spend a lot of time to wiping the lines on the blackboard. The chalk dust will pollute the air and environment in the classroom.
So we decided to create tool which is convenient and fast to draw straight lines easily.It doesn't pollute the classroom environment and maintain fresh air quality.
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| Can't draw straight line |
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| chalk dust pollute |
