| 摘要 |
A ruler for measuring and marking lengths and angles, relative to a horizontal plane by utilizing gravity. The ruler includes a substrate for being oriented relative to a horizontal plane and for measuring and marking lengths, and angle measuring assembly associated with the substrate for measuring and marking angles. The angle measuring assembly has a pointer whose lowermost end is heavier than its uppermost end, which allows the pointer to always remain vertical, regardless what angle the substrate is oriented relative to the horizontal plane, with the tangle the substrate is oriented relative to the horizontal plane being the angle to be measured and being that angular increment of a scale of the angle measuring assembly that the pointer points too.
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