/*
To convert a 2d shape into polygons

1) mirror on x axis (to correct for different origins.)
2) export as svg.
3) open svg in text editor
4) delete everything upto first 'M'
5) delete everything after last 'z'
6) search and replace 'L' with '],['
7) search and replace 'M' with 'polygon(points=[['
8) search and replace 'z' with ']]);'
9) if more than one polygon(if single shape) start with 'difference(){' and end with '}'
10) the result is the required polygons.
*/

module shape(){  // test composed of basic shapes
  rotate([0,0,20])
    difference(){
      square(450,true);
        square(200); 
        circle(100);
                }
}


mirror([0,1])  //  1) & 2)
shape();

/*  3)
<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="578mm" height="578mm" viewBox="-289 -289 578 578" xmlns="http://www.w3.org/2000/svg" version="1.1">
<title>OpenSCAD Model</title>
<path d="
M 288.385,-134.476 L -134.476,-288.385 L -288.385,134.476 L 134.476,288.385 z
M -68.404,187.939 L -34.0147,93.4545 L -43.8371,89.8794 L -61.5661,78.8011 L -76.6044,64.2788 L -88.2948,46.9472
 L -96.1262,27.5637 L -99.7564,6.97565 L -99.0268,-13.9173 L -93.9693,-34.202 L -84.8048,-52.9919 L -71.934,-69.4658
 L -55.9193,-82.9038 L -37.4607,-92.7184 L -17.3648,-98.4808 L 3.48995,-99.9391 L 24.1922,-97.0296 L 43.8371,-89.8794
 L 61.5661,-78.8011 L 76.6044,-64.2788 L 88.2948,-46.9472 L 96.1262,-27.5637 L 99.7564,-6.97565 L 99.0268,13.9173
 L 93.9693,34.202 L 187.939,68.404 L 119.534,256.343 z
" stroke="black" fill="lightgray" stroke-width="0.5"/>
</svg>

*/

/*  4) & 5)

M 288.385,-134.476 L -134.476,-288.385 L -288.385,134.476 L 134.476,288.385 z
M -68.404,187.939 L -34.0147,93.4545 L -43.8371,89.8794 L -61.5661,78.8011 L -76.6044,64.2788 L -88.2948,46.9472
 L -96.1262,27.5637 L -99.7564,6.97565 L -99.0268,-13.9173 L -93.9693,-34.202 L -84.8048,-52.9919 L -71.934,-69.4658
 L -55.9193,-82.9038 L -37.4607,-92.7184 L -17.3648,-98.4808 L 3.48995,-99.9391 L 24.1922,-97.0296 L 43.8371,-89.8794
 L 61.5661,-78.8011 L 76.6044,-64.2788 L 88.2948,-46.9472 L 96.1262,-27.5637 L 99.7564,-6.97565 L 99.0268,13.9173
 L 93.9693,34.202 L 187.939,68.404 L 119.534,256.343 z

 */
 
 /* 6)
 
M 288.385,-134.476 ],[ -134.476,-288.385 ],[ -288.385,134.476 ],[ 134.476,288.385 z
M -68.404,187.939 ],[ -34.0147,93.4545 ],[ -43.8371,89.8794 ],[ -61.5661,78.8011 ],[ -76.6044,64.2788 ],[ -88.2948,46.9472
 ],[ -96.1262,27.5637 ],[ -99.7564,6.97565 ],[ -99.0268,-13.9173 ],[ -93.9693,-34.202 ],[ -84.8048,-52.9919 ],[ -71.934,-69.4658
 ],[ -55.9193,-82.9038 ],[ -37.4607,-92.7184 ],[ -17.3648,-98.4808 ],[ 3.48995,-99.9391 ],[ 24.1922,-97.0296 ],[ 43.8371,-89.8794
 ],[ 61.5661,-78.8011 ],[ 76.6044,-64.2788 ],[ 88.2948,-46.9472 ],[ 96.1262,-27.5637 ],[ 99.7564,-6.97565 ],[ 99.0268,13.9173
 ],[ 93.9693,34.202 ],[ 187.939,68.404 ],[ 119.534,256.343 z

*/
 
/*  7) 
polygon(points=[[ 288.385,-134.476 ],[ -134.476,-288.385 ],[ -288.385,134.476 ],[ 134.476,288.385 z
polygon(points=[[ -68.404,187.939 ],[ -34.0147,93.4545 ],[ -43.8371,89.8794 ],[ -61.5661,78.8011 ],[ -76.6044,64.2788 ],[ -88.2948,46.9472
 ],[ -96.1262,27.5637 ],[ -99.7564,6.97565 ],[ -99.0268,-13.9173 ],[ -93.9693,-34.202 ],[ -84.8048,-52.9919 ],[ -71.934,-69.4658
 ],[ -55.9193,-82.9038 ],[ -37.4607,-92.7184 ],[ -17.3648,-98.4808 ],[ 3.48995,-99.9391 ],[ 24.1922,-97.0296 ],[ 43.8371,-89.8794
 ],[ 61.5661,-78.8011 ],[ 76.6044,-64.2788 ],[ 88.2948,-46.9472 ],[ 96.1262,-27.5637 ],[ 99.7564,-6.97565 ],[ 99.0268,13.9173
 ],[ 93.9693,34.202 ],[ 187.939,68.404 ],[ 119.534,256.343 z

*/

/* 8)

polygon(points=[[ 288.385,-134.476 ],[ -134.476,-288.385 ],[ -288.385,134.476 ],[ 134.476,288.385 ]]);
polygon(points=[[ -68.404,187.939 ],[ -34.0147,93.4545 ],[ -43.8371,89.8794 ],[ -61.5661,78.8011 ],[ -76.6044,64.2788 ],[ -88.2948,46.9472
 ],[ -96.1262,27.5637 ],[ -99.7564,6.97565 ],[ -99.0268,-13.9173 ],[ -93.9693,-34.202 ],[ -84.8048,-52.9919 ],[ -71.934,-69.4658
 ],[ -55.9193,-82.9038 ],[ -37.4607,-92.7184 ],[ -17.3648,-98.4808 ],[ 3.48995,-99.9391 ],[ 24.1922,-97.0296 ],[ 43.8371,-89.8794
 ],[ 61.5661,-78.8011 ],[ 76.6044,-64.2788 ],[ 88.2948,-46.9472 ],[ 96.1262,-27.5637 ],[ 99.7564,-6.97565 ],[ 99.0268,13.9173
 ],[ 93.9693,34.202 ],[ 187.939,68.404 ],[ 119.534,256.343 ]]);

*/

difference(){
polygon(points=[[ 288.385,-134.476 ],[ -134.476,-288.385 ],[ -288.385,134.476 ],[ 134.476,288.385 ]]);
polygon(points=[[ -68.404,187.939 ],[ -34.0147,93.4545 ],[ -43.8371,89.8794 ],[ -61.5661,78.8011 ],[ -76.6044,64.2788 ],[ -88.2948,46.9472
 ],[ -96.1262,27.5637 ],[ -99.7564,6.97565 ],[ -99.0268,-13.9173 ],[ -93.9693,-34.202 ],[ -84.8048,-52.9919 ],[ -71.934,-69.4658
 ],[ -55.9193,-82.9038 ],[ -37.4607,-92.7184 ],[ -17.3648,-98.4808 ],[ 3.48995,-99.9391 ],[ 24.1922,-97.0296 ],[ 43.8371,-89.8794
 ],[ 61.5661,-78.8011 ],[ 76.6044,-64.2788 ],[ 88.2948,-46.9472 ],[ 96.1262,-27.5637 ],[ 99.7564,-6.97565 ],[ 99.0268,13.9173
 ],[ 93.9693,34.202 ],[ 187.939,68.404 ],[ 119.534,256.343 ]]);

}