Sign up for an Award
Participate with your entry in one of our professional or student awards.Sign up for an award
You are using an outdated browser. Please upgrade your browser to improve your experience.
Paper is too long and your ruler is always too shirt.
Sometimes you really have to draw a stright and long line. But long ruler is hard
to carry at your side all the time.
A convex and a180°-groove make the ruler easy to spin half circle. You can keep drawing the stright line.
It will also incline on the plane naturally.Make your ruler easier to pick up
National Kaohsiung Normal University