add doc

README.md

@@ -196,10 +196,10 @@ See [examples](examples).
 - [noise/nz_perlin2s](https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_perlin2s.html)
 - [noise/nz_perlin3](https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_perlin3.html)
 - [noise/nz_perlin3s](https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_perlin3s.html)
-- noise/nz_worley1
-- noise/nz_worley1s
-- noise/nz_worley2
+- [noise/nz_worley2](https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_worley2.html)
 - noise/nz_worley2s
+- noise/nz_worley3
+- noise/nz_worley3s
 - noise/nz_cell
 
 ## Bugs and Feedback

docs/lib2x-nz_worley2.md

@@ -0,0 +1,53 @@
+# nz_worley2
+
+Returns the 2D [Worley noise](https://en.wikipedia.org/wiki/Worley_noise) value `[cell_x, cell_y, noise]` at the (x, y) coordinate. 
+
+It divides the space into tiles. The nucleus of each cell is randomly placed in a tile. 
+
+![nz_worley2](images/lib2x-nz_worley2-1.JPG)
+
+**Since:** 2.3
+
+## Parameters
+
+- `x` : The x coordinate.
+- `y` : The y coordinate.
+- `seed` : The random seed.
+- `tile_w` : The tile width. Default to 10. Smaller `tile_w` makes more cells.
+- `dist` : The noise value of each point is based on its distance to other cells. Different distance strategies make different noises. The `dist` parameter accepts `"euclidean"`, `"manhattan"`, `"chebyshev"` or `"border"`.
+
+## Examples
+
+    use <noise/nz_worley2.scad>;
+    use <util/dedup.scad>;
+
+    size = [100, 50];
+    tile_w = 10;
+    dist = "euclidean"; // [euclidean, manhattan, chebyshev, border] 
+    seed = 51;
+
+    points = [
+        for(y = [0:size[1] - 1]) 
+            for(x = [0:size[0] - 1]) 
+                [x, y]
+    ];
+
+    cells = [for(p = points) nz_worley2(p[0], p[1], seed, tile_w, dist)];
+
+    max_dist = max([for(c = cells) c[2]]);
+    for(i = [0:len(cells) - 1]) {
+        c = cells[i][2] / max_dist;
+        color([c, c, c])
+        linear_extrude(cells[i][2])
+        translate(points[i])
+            square(1);
+    }
+
+    cells_pts = dedup([for(c = cells) [c[0], c[1]]]);
+    for(p = cells_pts) {
+        translate(p)
+        linear_extrude(max_dist)
+            square(1);
+    }
+
+![nz_worley2](images/lib2x-nz_worley2-2.JPG)

src/noise/nz_worley2.scad

@@ -1,3 +1,13 @@
+/**
+* nz_worley2.scad
+*
+* @copyright Justin Lin, 2020
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_worley2.html
+*
+**/
+
 use <util/rand.scad>;
 use <noise/_impl/_nz_worley2_impl.scad>;