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docs/lib-torus_knot.md

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+# torus_knot 
+
+Generate a path of [The (p,q)-torus knot](https://en.wikipedia.org/wiki/Torus_knot).
+
+![torus_knot](images/lib-torus_knot-1.JPG)
+
+## Parameters
+
+- `p` : The p parameter of The (p,q)-torus knot. 
+- `q` : The q parameter of The (p,q)-torus knot. 
+- `phi_step`  : The amount when increasing phi. 
+
+## Examples
+
+	include <shape_pentagram.scad>;
+	include <rotate_p.scad>;
+	include <polysections.scad>;
+	include <path_extrude.scad>;
+	include <torus_knot.scad>;
+
+	p = 2;
+	q = 3;
+	phi_step = 0.05;
+	star_radius = 0.5;
+
+	pts = torus_knot(p, q, phi_step);
+
+	shape_pentagram_pts = shape_pentagram(star_radius);
+
+	path_extrude(
+		shape_pentagram_pts, 
+		concat(pts, [pts[0]]), 
+		closed = true
+	);
+
+![torus_knot](images/lib-torus_knot-2.JPG)
+