1  // https://www.cs.purdue.edu/homes/gnf/book2/trisqu.html
 2  function triangle2square(tri_side_leng) = 
 3      let(
 4          p0 = [0, 0],
 5          p1 = tri_side_leng * [0.25, 0.4330125],
 6          p2 = tri_side_leng * [0.5, 0.8660255],
 7          p4 = tri_side_leng * [1, 0],
 8          p3 = tri_side_leng * [0.75, 0.4330125],
 9          p6 = tri_side_leng * [0.254508, 0],
10          p5 = tri_side_leng * [0.754508, 0],
11          p8 = tri_side_leng * [0.5380015, 0.247745],
12          p7 = tri_side_leng * [0.4665065, 0.1852665],
13          pieces = [
14              [p0, p6, p7, p1],
15              [p6, p5, p8],
16              [p5, p4, p3, p8],
17              [p1, p7, p3, p2]
18          ],
19          hinged_pts = [p5, p3, p1]
20      )
21      [pieces, hinged_pts];