| 摘要 |
A drafting aid particularly useful for association with T-squares and the like wherein a vertical or normal datum point is easily obtained and wherein the drafting aid is movable about the extent of the T-square or other linear edge with which the device is used. In an exemplary embodiment the drafting aid comprises a vertically oriented member in association with a ruler or the like comprising the linear edge and the combination is associated with a T-square so as to have not only a means of aiding in the placement of vertical reference lines but also a means of ease of measuring distances between vertical reference points or lines.
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