| 摘要 |
Right angle templates, including rulers, are provided along their longer straight drawing edge (21) with a row of point-holes (11) corresponding to the main graduations of the measurement scale. Recesses (13, 14) are aligned with respect to a slot (12) which forms the starting point of the row of holes. A retainer part (50) may be inserted into those recesses (13, 14), and a rotation point (51) of their retainer part pierces then the drawing through the slot orifice, thereby enabling to draw circles according to the distances determined by the holes. It is also possible to draw circles of any radius by displacing the rotation point. By inserting the retainer part into the recesses (33, 34) it is possible to place the rotational point at the intersection center (22) of a goniometer, thereby enabling to draw angles and lines by a simple rotation. The insertion side to side of two retainer parts transforms the drawing instrument into a fixed guide rail.
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