Template for technical drawing and construction of certain geometrical figures consists of a transparent plastic material, and is a combination of equilateral triangles with progressively increasing side lengths
摘要
<p>The template for technical drawing and construction of certain geometrical figures consists of a transparent plastic material, and is a combination of equilateral triangles whose sides measure respectively 1, 3, 5, 7, 9, 11 and 13 units.</p>
