| 摘要 |
The Thread Ruler and Multi-Function Drafting Instrument is a single instrument designed to draw circles, ellipses and parallel lines, and which includes features that allow the instrument to function as protractor, a ruler and a drawing compass. The instrument has a slide ruler that holds a marking device and that has a stem with a thread attached. The thread is further attached to the main ruler body at an outer end of the protractor so that ellipses can be drawn. The instrument may be used on any flat marking surface including: paper, drafting table, chalkboard and dry erased board. The instrument may be adapted to be used in portable manner so that it can be placed in shirt pocket.
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