add doc

README.md

@@ -236,7 +236,7 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 ### Path
 
 - [curve](https://openhome.cc/eGossip/OpenSCAD/lib2x-curve.html)
-- bauer_spiral
+- [bauer_spiral](https://openhome.cc/eGossip/OpenSCAD/lib2x-bauer_spiral.html)
 - fibonacci_lattice
 
 ### Voxel

docs/lib2x-bauer_spiral.md

@@ -0,0 +1,33 @@
+# bauer_spiral
+
+Creates visually even spacing of n points on the surface of the sphere. Successive points will all be approximately the same distance apart. 
+
+(It's called "visually even spacing" because only the vertices of the 5 [Platonic solids](https://en.wikipedia.org/wiki/Platonic_solid) can be said to be truly evenly spaced around the surface of a sphere.)
+
+## Parameters
+
+- `n` : The number of points.
+- `radius` : The sphere radius. Default to 1.
+- `rt_dir` : `"CT_CLK"` for counterclockwise. `"CLK"` for clockwise. The default value is `"CT_CLK"`.
+
+## Examples
+
+    use <bauer_spiral.scad>;
+    use <hull_polyline3d.scad>;
+
+    n = 200;
+    radius = 20;
+    pts = bauer_spiral(n, radius);
+
+    for(p = pts) {
+        translate(p)
+            sphere(1, $fn = 24);
+    }
+
+    hull_polyline3d(pts, 1);
+
+![bauer_spiral](images/lib2x-bauer_spiral-1.JPG)
+
+You can use it to create [Text sphere](https://cults3d.com/en/3d-model/art/bauer-text-sphere).
+
+![bauer_spiral](images/lib2x-bauer_spiral-2.JPG)

src/bauer_spiral.scad

@@ -1,9 +1,19 @@
-function bauer_spiral(n, radius = 1, dir = "CT_CLK") = 
+/**
+* bauer_spiral.scad
+*
+* @copyright Justin Lin, 2019
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib2x-bauer_spiral.html
+*
+**/
+
+function bauer_spiral(n, radius = 1, rt_dir = "CT_CLK") = 
     let(
         L = sqrt(n * PI),
         toRadians = PI / 180,
         toDegrees = 180 / PI,
-        clk = dir == "CT_CLK" ? 1 : -1
+        clk = rt_dir == "CT_CLK" ? 1 : -1
     )
     [
         for(k = 1; k <= n; k = k + 1)