add deprecated msg

README.md

@@ -1,4 +1,4 @@
-# dotSCAD 3.2.2
+# dotSCAD 3.3
 
 > **Reduce the burden of mathematics/algorithm when playing OpenSCAD.**
 
@@ -18,13 +18,13 @@ OpenSCAD uses three library locations, the installation library, built-in librar
 
 Every public module/function has the same name as the .scad file. Here's an example using the `line2d` module: 
 
-	use <line2d.scad>;
+	use <line2d.scad>
 
 	line2d(p1 = [0, 0], p2 = [5, 0], width = 1);
 
 The library uses directories to categorize some modules/functions. For example, vx_circle.scad exists in `voxel` directory. Prefix the directory name when using `vx_circle`.
 
-    use <voxel/vx_circle.scad>;
+    use <voxel/vx_circle.scad>
 	
 	points = vx_circle(radius = 10);
 	for(pt = points) {
@@ -94,7 +94,6 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 [**cross_sections**(shape_pts, path_pts, angles[, twist, scale])](https://openhome.cc/eGossip/OpenSCAD/lib3x-cross_sections.html) | given a 2D shape, points and angles along the path, this function returns all cross-sections.
 [**in_polyline**(line_pts, pt[, epsilon])](https://openhome.cc/eGossip/OpenSCAD/lib3x-in_polyline.html) | check whether a point is on a line.
 [**lines_intersection**(line1, line2[, ext, epsilon])](https://openhome.cc/eGossip/OpenSCAD/lib3x-lines_intersection.html) | find the intersection of two line segments. Return `[]` if lines don't intersect.
-[**rails2sections**(rails)](https://openhome.cc/eGossip/OpenSCAD/lib3x-rails2sections.html) | create sections along rails.
 [**path_scaling_sections**(shape_pts, edge_path)](https://openhome.cc/eGossip/OpenSCAD/lib3x-path_scaling_sections.html) | given an edge path with the first point at the outline of a shape, this function uses the path to calculate scaling factors and returns all scaled sections in the reversed order of the edge path. 
 [**midpt_smooth**(points, n[, closed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-midpt_smooth.html) | given a 2D path, this function constructs a mid-point smoothed version by joining the mid-points of the lines of the path.
 
@@ -159,19 +158,20 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 
  Signature | Description
 --|--
-[**util/bsearch**(sorted, target)](https://openhome.cc/eGossip/OpenSCAD/lib3x-bsearch.html) | search a value in a list whose elements must be sorted by zyx.
-[**util/has**(lt, elem[, sorted])](https://openhome.cc/eGossip/OpenSCAD/lib3x-has.html) | return `true` if `lt` contains elem.
+[**util/binary_search**(sorted, target[, lo, hi])](https://openhome.cc/eGossip/OpenSCAD/lib3x-binary_search.html) | search a value in a sorted list.
+[**util/contains**(lt, elem)](https://openhome.cc/eGossip/OpenSCAD/lib3x-contains.html) | return `true` if `lt` contains `elem`.
 [**util/find_index**(lt, test)](https://openhome.cc/eGossip/OpenSCAD/lib3x-find_index.html) | return the index of the first element that satisfies the testing function. 
 [**util/dedup**(lt, ...)](https://openhome.cc/eGossip/OpenSCAD/lib3x-dedup.html) | eliminate duplicate vectors.
 [**util/flat**(lt[, depth])](https://openhome.cc/eGossip/OpenSCAD/lib3x-flat.html) | return a new list with all sub-list elements concatenated into it recursively up to the specified depth.
 [**util/reverse**(lt)](https://openhome.cc/eGossip/OpenSCAD/lib3x-reverse.html) | reverse a list.
 [**util/slice**(lt, begin, end)](https://openhome.cc/eGossip/OpenSCAD/lib3x-slice.html) | return a list selected from `begin` to `end`, or to the `end` of the list (`end` not included).
-[**util/sort**(lt[, by, idx])](https://openhome.cc/eGossip/OpenSCAD/lib3x-sort.html) | sort a list.
+[**util/sorted**(lt[, cmp, key, reverse])](https://openhome.cc/eGossip/OpenSCAD/lib3x-sorted.html) | sort a list.
 [**util/sum**(lt)](https://openhome.cc/eGossip/OpenSCAD/lib3x-sum.html) | use `+` to sum up all elements in a list.
 [**util/swap**(lt, i, j)](https://openhome.cc/eGossip/OpenSCAD/lib3x-swap.html) | swap two elements in a list.
 [**util/zip**(lts, combine)](https://openhome.cc/eGossip/OpenSCAD/lib3x-zip.html) | make a list that aggregates elements from each of the lists.
 [**util/every**(lt, test)](https://openhome.cc/eGossip/OpenSCAD/lib3x-every.html) | test whether all elements in the list pass the test implemented by the provided function.
 [**util/some**(lt, test)](https://openhome.cc/eGossip/OpenSCAD/lib3x-some.html) | test whether at least one element in the list passes the test implemented by the provided function.
+[**util/count**(lt, test)](https://openhome.cc/eGossip/OpenSCAD/lib3x-count.html) | return the number of times `test` return `true` in the list.
 
 ### util/random
 
@@ -235,6 +235,7 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 [**matrix/m_shearing**([sx, sy, sz])](https://openhome.cc/eGossip/OpenSCAD/lib3x-m_shearing.html) | generate a transformation matrix which can pass into `multmatrix` to shear all child elements along the X-axis, Y-axis, or Z-axis in 3D.
 [**matrix/m_translation**(v)](https://openhome.cc/eGossip/OpenSCAD/lib3x-m_translation.html) | generate a transformation matrix which can pass into multmatrix to translates (moves) its child elements along the specified vector.
 [**maxtrix/m_transpose**(m)](https://openhome.cc/eGossip/OpenSCAD/lib3x-m_transpose.html) | transpose a matrix.
+[**matrix/m_replace**(m, i, j, value)](https://openhome.cc/eGossip/OpenSCAD/lib3x-m_replace.html) | replace the aᵢⱼ element of a matrix.
 
 ## Point Transformation
 
@@ -260,6 +261,7 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 [**triangle/tri_delaunay_indices**(d)](https://openhome.cc/eGossip/OpenSCAD/lib3x-tri_delaunay_indices.html) | return triangle indices from a delaunay object.
 [**triangle/tri_delaunay_shapes**(d)](https://openhome.cc/eGossip/OpenSCAD/lib3x-tri_delaunay_shapes.html) | return triangle shapes from a delaunay object.
 [**triangle/tri_delaunay_voronoi**(d)](https://openhome.cc/eGossip/OpenSCAD/lib3x-tri_delaunay_voronoi.html) | return [Voronoi](https://en.wikipedia.org/wiki/Voronoi_diagram) cells from a delaunay object.
+[**triangle/tri_subdivide**(shape_pts[, n])](https://openhome.cc/eGossip/OpenSCAD/lib3x-tri_subdivide.html) | subdivide a triangle `n` times.
 
 ----
 
@@ -349,14 +351,15 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 
  Signature | Description
 --|--
-[**maze/mz_square_cells**(rows, columns[, start, ...])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_square_cells.html) | return cell data of a square maze.
+[**maze/mz_square**([rows, columns, start, init_cells, x_wrapping, y_wrapping, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_square.html) | return cell data of a square maze.
 [**maze/mz_square_get**(cell, query)](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_square_get.html) | a helper for getting data from a square-maze cell.
-[**maze/mz_square_walls**(cells, rows, columns, cell_width, ...)](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_square_walls.html) | a helper for creating square wall data from maze cells.
-[**maze/mz_hex_walls**(cells, rows, columns, cell_radius, ...)](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_hex_walls.html) | a helper for creating hex wall data from maze cells.
+[**maze/mz_squarewalls**(cells, cell_width[, left_border, bottom_border])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_squarewalls.html) | a helper for creating square wall data from maze cells.
+[**maze/mz_hexwalls**(cells, cell_radius[, left_border, bottom_border])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_hexwalls.html) | a helper for creating hex wall data from maze cells.
 [**maze/mz_square_initialize**(rows, columns, mask)](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_square_initialize.html) | a helper for initializing cell data of a maze.
 [**maze/mz_hamiltonian**(rows, columns[, start, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_hamiltonian.html) | create a hamiltonian path from a maze.
 [**maze/mz_theta_cells**(rows, beginning_number[, start, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_theta_cells.html) | return cell data of a theta maze.
-[**maze/mz_theta_get**(cell, query)](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_theta_get.html) | a helper for getting data from a theta-maze cell.
+[**maze/mz_theta**(rings, beginning_number[, start, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_theta.html) | return cell data of a theta maze.
+[**maze/mz_tiles**(cells[, left_border, bottom_border])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_tiles.html) | turn maze cells into tiles.
 
 ## Polyhedra
 
@@ -371,5 +374,13 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 [**polyhedra/icosahedron**(radius[, detail])](https://openhome.cc/eGossip/OpenSCAD/lib3x-polyhedra_icosahedron.html) | create a icosahedron.
 [**polyhedra/superellipsoid**(radius[, detail])](https://openhome.cc/eGossip/OpenSCAD/lib3x-polyhedra_superellipsoid.html) | create a superellipsoid.
 
-----
+## Point Picking
 
+ Signature | Description
+--|--
+[**pp/pp_disk**(radius, value_count[, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-pp_disk.html) | generate random points over a disk.
+[**pp/pp_sphere**(radius, value_count[, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-pp_sphere.html) | pick random points on the surface of a sphere.
+[**pp/pp_poisson2**(size, r[, start, k, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-pp_poisson2.html) | perform poisson sampling over a rectangle area.
+[**pp/pp_poisson3**(size, r[, start, k, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-pp_poisson3.html) | perform poisson sampling over a cube space.
+
+----

RELEASE.md

@@ -1,5 +1,62 @@
 > Version numbers are based on [Semantic Versioning](https://semver.org/).
 
+# v3.3
+
+## Deprecated
+
+ Signature | Description
+--|--
+**rails2sections** | use [`maxtrix/m_transpose`](https://openhome.cc/eGossip/OpenSCAD/lib3x-m_transpose.html) instead.
+**util/sort** | use [`util/sorted`](https://openhome.cc/eGossip/OpenSCAD/lib3x-sorted.html) instead.
+**util/has** | use [`util/contains`](https://openhome.cc/eGossip/OpenSCAD/lib3x-contains.html) instead.
+**util/bsearch** | use [`util/binary_search`](https://openhome.cc/eGossip/OpenSCAD/lib3x-binary_search.html) instead.
+**maze/mz_square_cells** | use [`maze/mz_square`](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_square.html).
+**maze/mz_square_walls** | use [`maze/mz_squarewalls`](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_squarewalls.html) instead.
+**maze/mz_hex_walls** | use [`maze/mz_hexwalls`](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_hexwalls.html) instead.
+**maze/mz_theta_cells** | use [`maze/mz_theta`](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_theta.html) instead.
+
+
+## Util
+
+ Signature | Description
+--|--
+[**util/sorted**(lt[, cmp, key, reverse])](https://openhome.cc/eGossip/OpenSCAD/lib3x-sorted.html) | sort a list.
+[**util/contains**(lt, elem)](https://openhome.cc/eGossip/OpenSCAD/lib3x-contains.html) | return `true` if `lt` contains `elem`.
+[**util/binary_search**(sorted, target[, lo, hi])](https://openhome.cc/eGossip/OpenSCAD/lib3x-binary_search.html) | search a value in a sorted list.
+[**util/count**(lt, test)](https://openhome.cc/eGossip/OpenSCAD/lib3x-count.html) | return the number of times `test` return `true` in the list.
+
+## Matrix
+
+ Signature | Description
+--|--
+[**matrix/m_replace**(m, i, j, value)](https://openhome.cc/eGossip/OpenSCAD/lib3x-m_replace.html) | replace the aᵢⱼ element of a matrix.
+
+## Triangle
+
+ Signature | Description
+--|--
+[**triangle/tri_subdivide**(shape_pts[, n])](https://openhome.cc/eGossip/OpenSCAD/lib3x-tri_subdivide.html) | subdivide a triangle `n` times.
+
+## Point Picking
+
+ Signature | Description
+--|--
+[**pp/pp_disk**(radius, value_count[, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-pp_disk.html) | generate random points over a disk.
+[**pp/pp_sphere**(radius, value_count[, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-pp_sphere.html) | pick random points on the surface of a sphere.
+[**pp/pp_poisson2**(size, r[, start, k, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-pp_poisson2.html) | perform poisson sampling over a rectangle area.
+[**pp/pp_poisson3**(size, r[, start, k, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-pp_poisson3.html) | perform poisson sampling over a cube space.
+
+## Maze
+
+ Signature | Description
+--|--
+[**maze/mz_square**([rows, columns, start, init_cells, x_wrapping, y_wrapping, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_square.html) | return cell data of a square maze.
+[**maze/mz_squarewalls**(cells, cell_width[, left_border, bottom_border])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_squarewalls.html) | a helper for creating square wall data from maze cells.
+[**maze/mz_hexwalls**(cells, cell_radius[, left_border, bottom_border])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_hexwalls.html) | a helper for creating hex wall data from maze cells.
+[**maze/mz_theta**(rings, beginning_number[, start, seed])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_theta.html) | return cell data of a theta maze.
+[**maze/mz_tiles**(cells[, left_border, bottom_border])](https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_tiles.html) | turn maze cells into tiles.
+
+
 # v3.2.2
 
 Maintenance release: bug fixes & performance improvements.

docs/lib3x-along_with.md

@@ -12,8 +12,8 @@ If you want to place objects precisely, their points and angles are required. Wh
 
 ## Examples
 
-	use <along_with.scad>;
-	use <shape_circle.scad>;
+	use <along_with.scad>
+	use <shape_circle.scad>
 	
 	$fn = 24;
 	
@@ -24,8 +24,8 @@ If you want to place objects precisely, their points and angles are required. Wh
 
 ![along_with](images/lib3x-along_with-1.JPG)
 
-	use <along_with.scad>;
-	use <shape_circle.scad>;
+	use <along_with.scad>
+	use <shape_circle.scad>
 
 	$fn = 24;
 
@@ -44,8 +44,8 @@ If you want to place objects precisely, their points and angles are required. Wh
 
 ![along_with](images/lib3x-along_with-2.JPG)
 
-	use <along_with.scad>;
-	use <golden_spiral.scad>;
+	use <along_with.scad>
+	use <golden_spiral.scad>
 
 	pts_angles = golden_spiral(
 		from = 5, 
@@ -63,8 +63,8 @@ If you want to place objects precisely, their points and angles are required. Wh
 
 ![along_with](images/lib3x-along_with-3.JPG)
 
-	use <bezier_curve.scad>;
-	use <along_with.scad>;
+	use <bezier_curve.scad>
+	use <along_with.scad>
 
 	module scales() {
 		module one_scale() {

docs/lib3x-angle_between.md

@@ -11,7 +11,7 @@ Returns the angle between two vectors.
 
 ## Examples
 
-    use <angle_between.scad>;
+    use <angle_between.scad>
 
     assert(angle_between([0, 1], [1, 0]) == 90);
     assert(angle_between([0, 1, 0], [1, 0, 0]) == 90);

docs/lib3x-arc.md

@@ -13,7 +13,7 @@ Creates an arc. You can pass a 2 element vector to define the central angle. Its
 
 ## Examples
   
-    use <arc.scad>;
+    use <arc.scad>
     
     $fn = 24;
     arc(radius = 20, angle = [45, 290], width = 2);
@@ -21,7 +21,7 @@ Creates an arc. You can pass a 2 element vector to define the central angle. Its
 
 ![arc](images/lib3x-arc-1.JPG)
 
-    use <arc.scad>;
+    use <arc.scad>
     
     $fn = 24;
     arc(radius = 20, angle = [45, 290], width = 2, width_mode = "LINE_OUTWARD");
@@ -29,7 +29,7 @@ Creates an arc. You can pass a 2 element vector to define the central angle. Its
 
 ![arc](images/lib3x-arc-2.JPG)
 
-    use <arc.scad>;
+    use <arc.scad>
     
     $fn = 24;
     arc(radius = 20, angle = [45, 290], width = 2, width_mode = "LINE_INWARD");

docs/lib3x-arc_path.md

@@ -11,8 +11,8 @@ Creates an arc path. You can pass a 2 element vector to define the central angle
 
 ## Examples
   
-	use <arc_path.scad>;
-	use <polyline_join.scad>;
+	use <arc_path.scad>
+	use <polyline_join.scad>
 
 	$fn = 24;
 	points = arc_path(radius = 20, angle = [45, 290]);
@@ -21,8 +21,8 @@ Creates an arc path. You can pass a 2 element vector to define the central angle
 
 ![arc_path](images/lib3x-arc_path-1.JPG)
 
-    use <arc_path.scad>;
-    use <polyline_join.scad>;
+    use <arc_path.scad>
+    use <polyline_join.scad>
     
     $fn = 24;
     points = arc_path(radius = 20, angle = 135);

docs/lib3x-archimedean_spiral.md

@@ -16,8 +16,8 @@ An `init_angle` less than 180 degrees is not recommended because the function us
 
 ## Examples
 
-	use <polyline2d.scad>;
-    use <archimedean_spiral.scad>;
+	use <polyline2d.scad>
+    use <archimedean_spiral.scad>
 	
 	points_angles = archimedean_spiral(
 	    arm_distance = 10,
@@ -32,7 +32,7 @@ An `init_angle` less than 180 degrees is not recommended because the function us
 
 ![archimedean_spiral](images/lib3x-archimedean_spiral-1.JPG)
 	
-    use <archimedean_spiral.scad>;
+    use <archimedean_spiral.scad>
     
 	points_angles = archimedean_spiral(
 	    arm_distance = 10,  
@@ -48,7 +48,7 @@ An `init_angle` less than 180 degrees is not recommended because the function us
 
 ![archimedean_spiral](images/lib3x-archimedean_spiral-2.JPG)
 	
-	use <archimedean_spiral.scad>;
+	use <archimedean_spiral.scad>
 	
 	t = "3.141592653589793238462643383279502884197169399375105820974944592307816406286";
 	

docs/lib3x-archimedean_spiral_extrude.md

@@ -14,7 +14,7 @@ When using this module, you should use points to represent the 2D shape. If your
 
 ## Examples
     
-	use <archimedean_spiral_extrude.scad>;
+	use <archimedean_spiral_extrude.scad>
 
 	shape_pts = [
 		[5, 0],

docs/lib3x-bauer_spiral.md

@@ -14,8 +14,8 @@ Creates visually even spacing of n points on the surface of the sphere. Successi
 
 ## Examples
 
-    use <bauer_spiral.scad>;
-    use <polyline_join.scad>;
+    use <bauer_spiral.scad>
+    use <polyline_join.scad>
 
     n = 200;
     radius = 20;

docs/lib3x-bend.md

@@ -12,7 +12,7 @@ Bends a 3D object into an arc shape.
 
 The containing cube of the target object should be laid down on the x-y plane. For example.
 
-    use <bend.scad>;
+    use <bend.scad>
 
 	x = 9.25;
 	y = 9.55;
@@ -25,7 +25,7 @@ The containing cube of the target object should be laid down on the x-y plane. F
 
 Once you have the size of the containing cube, you can use it as the `size` argument of the `bend` module.
 
-    use <bend.scad>;
+    use <bend.scad>
 
 	x = 9.25;
 	y = 9.55;
@@ -41,7 +41,7 @@ Once you have the size of the containing cube, you can use it as the `size` argu
 
 The arc shape is smoother if the `frags` value is larger. 
 
-    use <bend.scad>;
+    use <bend.scad>
 	
 	x = 9.25;
 	y = 9.55;

docs/lib3x-bend_extrude.md

@@ -25,7 +25,7 @@ The containing square of the target shape should be laid down on the x-y plane.
 
 Once you have the size of the containing square, you can use it as the `size` argument of the `bend_extrude` module.
 
-	use <bend_extrude.scad>;
+	use <bend_extrude.scad>
 
 	x = 9.25;
 	y = 9.55;

docs/lib3x-bezier_curve.md

@@ -11,8 +11,8 @@ Given a set of control points, the `bezier_curve` function returns points of the
 
 If you have four control points:
 
-    use <polyline_join.scad>;
-	use <bezier_curve.scad>;
+    use <polyline_join.scad>
+	use <bezier_curve.scad>
 
 	t_step = 0.05;
 	radius = 2;

docs/lib3x-bezier_smooth.md

@@ -12,8 +12,8 @@ Given a path, the `bezier_smooth` function uses bazier curves to smooth all corn
 
 ## Examples
 
-	use <polyline_join.scad>;
-	use <bezier_smooth.scad>;
+	use <polyline_join.scad>
+	use <bezier_smooth.scad>
 
 	width = 2;
 	round_d = 15;
@@ -37,7 +37,7 @@ Given a path, the `bezier_smooth` function uses bazier curves to smooth all corn
 
 ![bezier_smooth](images/lib3x-bezier_smooth-1.JPG)
 
-	use <bezier_smooth.scad>;
+	use <bezier_smooth.scad>
 
 	round_d = 10;
 

docs/lib3x-bijection_offset.md

@@ -12,7 +12,7 @@ Move 2D outlines outward or inward by a given amount. Each point of the offsette
 
 ## Examples
 
-	use <bijection_offset.scad>;
+	use <bijection_offset.scad>
 
 	shape = [
 		[15, 0],
@@ -32,9 +32,9 @@ Move 2D outlines outward or inward by a given amount. Each point of the offsette
 
 ![bijection_offset](images/lib3x-bijection_offset-1.JPG)
 
-	use <bijection_offset.scad>;
-	use <path_extrude.scad>;
-	use <bezier_curve.scad>;
+	use <bijection_offset.scad>
+	use <path_extrude.scad>
+	use <bezier_curve.scad>
 
 	shape = [
 		[5, 0],

docs/lib3x-binary_search.md

@@ -0,0 +1,28 @@
+# binary_search
+
+A general-purpose function to search a value in a sorted list.
+
+**Since:**  3.3
+
+## Parameters
+
+- `sorted` : The sorted list.
+- `target` : The target element or a function literal that returns a negative integer, zero, or a positive integer as the element is less than, equal to, or greater than the value you want to search.
+- `lo` : Default to 0. The lower bound to be searched.
+- `hi` : Default to the end of the list. The higher bound to be searched.
+
+## Examples
+
+    use <util/sorted.scad>
+    use <util/binary_search.scad>
+
+    points = [[1, 1], [3, 4], [7, 2], [5, 2]];
+    lt = sorted(points); // [[1, 1], [3, 4], [5, 2], [7, 2]]
+
+    assert(binary_search(lt, [7, 2]) == 3);
+
+    xIs5 = function(elem) elem[0] - 5;
+    assert(binary_search(lt, xIs5) == 2);
+
+    yIs4 = function(elem) elem[1] - 4;
+    assert(binary_search(lt, yIs4) == 1);

docs/lib3x-box_extrude.md

@@ -12,14 +12,14 @@ Creates a box (container) from a 2D object.
 
 ## Examples
 
-    use <box_extrude.scad>;
+    use <box_extrude.scad>
     
 	box_extrude(height = 30, shell_thickness = 2) 
 	    circle(r = 30);
 
 ![box_extrude](images/lib3x-box_extrude-1.JPG)
 
-    use <box_extrude.scad>;
+    use <box_extrude.scad>
     
 	box_extrude(height = 30, shell_thickness = 2) 
 	    text("XD", size = 40, font = "Cooper Black");

docs/lib3x-bsearch.md

@@ -11,8 +11,8 @@ The `bsearch` function is a general-purpose function to search a value in a list
 
 ## Examples
 
-	use <util/sort.scad>;
-	use <util/bsearch.scad>;
+	use <util/sort.scad>
+	use <util/bsearch.scad>
 
     points = [[1, 1], [3, 4], [7, 2], [5, 2]];
     sorted = sort(points, by = "vt"); //  [[1, 1], [5, 2], [7, 2], [3, 4]]

docs/lib3x-bspline_curve.md

@@ -14,7 +14,7 @@
 
 ## Examples
 
-    use <bspline_curve.scad>;
+    use <bspline_curve.scad>
     
 	points = [
 		[-10, 0],
@@ -37,7 +37,7 @@
 
 ![bspline_curve](images/lib3x-bspline_curve-1.JPG)
 
-    use <bspline_curve.scad>;
+    use <bspline_curve.scad>
     
 	points = [
 		[-10, 0],
@@ -62,7 +62,7 @@
 
 ![bspline_curve](images/lib3x-bspline_curve-2.JPG)
 
-	use <bspline_curve.scad>;
+	use <bspline_curve.scad>
 		
 	points = [
 		[-10, 0],

docs/lib3x-choose.md

@@ -11,6 +11,6 @@ Choose an element from the given list randomly.
 
 ## Examples
 
-    use <util/choose.scad>;
+    use <util/choose.scad>
     
     echo(choose([1, 2, 3, 4]));

docs/lib3x-circle_path.md

@@ -10,7 +10,7 @@ Sometimes you need all points on the path of a circle. Here's the function. Its
 
 ## Examples
 
-    use <circle_path.scad>;
+    use <circle_path.scad>
 
 	$fn = 24;
 	

docs/lib3x-cone.md

@@ -18,7 +18,7 @@ Create a cone for rotatable models.
 
 ## Examples
 
-	use <part/cone.scad>;
+	use <part/cone.scad>
 
 	radius = 2.5;
     length = 2;
@@ -41,7 +41,7 @@ Create a cone for rotatable models.
 
 ![cone](images/lib3x-cone-2.JPG)
 
-	use <part/cone.scad>;
+	use <part/cone.scad>
 
 	radius = 2.5;
     length = 2;

docs/lib3x-connector_peg.md

@@ -17,7 +17,7 @@ Create a connector peg.
 
 ## Examples
 
-	use <part/connector_peg.scad>;
+	use <part/connector_peg.scad>
 
 	radius = 2.5;
 	spacing = 0.5;
@@ -37,7 +37,7 @@ Create a connector peg.
 
 ![connector_peg](images/lib3x-connector_peg-1.JPG)
 
-	use <part/connector_peg.scad>;
+	use <part/connector_peg.scad>
 
 	radius = 2.5;
 	spacing = 0.5;

docs/lib3x-contains.md

@@ -0,0 +1,19 @@
+# contains
+
+If `lt` contains `elem`, this function returns `true`.
+
+**Since:** 3.3
+
+## Parameters
+
+- `lt` : A list of vectors.
+- `elem` : A element.
+
+## Examples
+
+    use <voxel/vx_circle.scad>
+    use <util/contains.scad>
+
+    pts = vx_circle(10);
+    assert(contains(pts, [2, -10])); 
+    assert(!contains(pts, [0, 0]));  

docs/lib3x-contours.md

@@ -11,9 +11,9 @@ Computes contour polygons by applying [marching squares](https://en.wikipedia.or
 
 ## Examples
 
-    use <polyline_join.scad>;
-	use <surface/sf_thicken.scad>;
-    use <contours.scad>;
+    use <polyline_join.scad>
+	use <surface/sf_thicken.scad>
+    use <contours.scad>
 
     min_value =  1;
     max_value = 360;

docs/lib3x-count.md

@@ -0,0 +1,15 @@
+# count
+
+Returns the number of times `test` return `true` in the list.
+
+**Since:** 3.3
+
+## Parameters
+
+- `lt` : The list.
+- `test` : A testing function.
+
+## Examples
+
+    points = [[7, 2, 2], [1, 1, 2], [3, 4, 2], [3, 4, 2], [1, 2, 3]];
+    assert(count(points, function(p) norm(p) > 5) == 3);

docs/lib3x-cross_sections.md

@@ -12,9 +12,9 @@ Given a 2D shape, points and angles along the path, this function will return al
 
 ## Examples
 
-	use <sweep.scad>;
-	use <cross_sections.scad>;
-	use <archimedean_spiral.scad>;
+	use <sweep.scad>
+	use <cross_sections.scad>
+	use <archimedean_spiral.scad>
 
 	shape_pts = [
 		[-2, -10],

docs/lib3x-crystal_ball.md

@@ -14,7 +14,7 @@ Uses spherical coordinate system to create a crystal ball.
 
 ## Examples
 
-	use <crystal_ball.scad>;
+	use <crystal_ball.scad>
 
 	crystal_ball(radius = 6);
 

docs/lib3x-curve.md

@@ -16,8 +16,8 @@ Draws a curved line from control points. The curve is drawn only from the 2nd co
 
 ## Examples
 
-	use <curve.scad>;
-	use <polyline_join.scad>;
+	use <curve.scad>
+	use <polyline_join.scad>
 
 	pts = [
 		[28, 2, 1],

docs/lib3x-dedup.md

@@ -13,6 +13,8 @@ Eliminating duplicate copies of repeating vectors.
 
 ## Examples
 
+    use <util/dedup.scad>
+
     eq = function(e1, e2) e1[0] == e2[0] && e1[1] == e2[1] && e1[2] == e2[2];
 
     points = [[1, 1, 2], [3, 4, 2], [7, 2, 2], [3, 4, 2], [1, 2, 3]];

docs/lib3x-degrees.md

@@ -10,6 +10,6 @@ Converts a radian measurement to the corresponding value in degrees.
 
 ## Examples
 		
-	use <util/degrees.scad>;
+	use <util/degrees.scad>
 		
 	assert(degrees(PI) == 180);  

docs/lib3x-ellipse_extrude.md

@@ -10,7 +10,7 @@ Extrudes a 2D object along the path of an ellipse from 0 to 180 degrees. The sem
 
 ## Examples
 
-	use <ellipse_extrude.scad>;
+	use <ellipse_extrude.scad>
 	
 	semi_minor_axis = 5;
 	 
@@ -19,7 +19,7 @@ Extrudes a 2D object along the path of an ellipse from 0 to 180 degrees. The sem
 
 ![ellipse_extrude](images/lib3x-ellipse_extrude-1.JPG)
 
-	use <ellipse_extrude.scad>;
+	use <ellipse_extrude.scad>
 	
 	semi_minor_axis = 5;
 	 
@@ -28,7 +28,7 @@ Extrudes a 2D object along the path of an ellipse from 0 to 180 degrees. The sem
 
 ![ellipse_extrude](images/lib3x-ellipse_extrude-2.JPG)
 
-    use <ellipse_extrude.scad>;
+    use <ellipse_extrude.scad>
 
 	semi_minor_axis = 5;
 	 
@@ -41,7 +41,7 @@ Extrudes a 2D object along the path of an ellipse from 0 to 180 degrees. The sem
 
 ![ellipse_extrude](images/lib3x-ellipse_extrude-3.JPG)
 
-	use <ellipse_extrude.scad>;
+	use <ellipse_extrude.scad>
 	
 	semi_minor_axis = 10;
 	 

docs/lib3x-every.md

@@ -11,7 +11,7 @@ The `every` function tests whether all elements in the list pass the test implem
 
 ## Examples
 
-    use <util/every.scad>;
+    use <util/every.scad>
    
     biggerThanZero = function(elem) elem > 0;
     assert(every([1, 30, 39, 29, 10, 13], biggerThanZero));

docs/lib3x-fibonacci_lattice.md

@@ -1,6 +1,6 @@
 # fibonacci_lattice
 
-Creates visually even spacing of n points on the surface of the sphere. Nearest-neighbor points will all be approximately the same distance apart. There're 8 spirals on the sphere.
+Creates visually even spacing of n points on the surface of the sphere. Nearest-neighbor 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.)
 
@@ -14,7 +14,7 @@ Creates visually even spacing of n points on the surface of the sphere. Nearest-
 
 ## Examples
 
-    use <fibonacci_lattice.scad>;
+    use <fibonacci_lattice.scad>
 
     n = 200;
     radius = 20;
@@ -29,9 +29,9 @@ Creates visually even spacing of n points on the surface of the sphere. Nearest-
 
 
 ![fibonacci_lattice](images/lib3x-fibonacci_lattice-1.JPG)
-
-    use <fibonacci_lattice.scad>;
-    use <polyline_join.scad>;
+    
+    use <fibonacci_lattice.scad>
+    use <polyline_join.scad>
 
     n = 200;
     radius = 20;
@@ -41,16 +41,18 @@ Creates visually even spacing of n points on the surface of the sphere. Nearest-
         translate(p)
             sphere(1);
     }
-        
-    sphere(radius);
 
-    spirals = [for(j = [0:7]) 
-        [for(i = j; i < len(pts); i = i + 8) pts[i]]
+    sphere(radius * 0.9);
+
+    // You can pick spirals from points.
+    spirals = [for(j = [0:20]) 
+        [for(i = j; i < len(pts); i = i + 21) pts[i]]
     ];
 
+
     for(spiral = spirals) {
         polyline_join(spiral)
-		    sphere(.5);	
+            sphere(.25); 
     }
         
 ![fibonacci_lattice](images/lib3x-fibonacci_lattice-2.JPG)

docs/lib3x-fibseq.md

@@ -11,6 +11,6 @@ Generate a Fibonacci sequence.
 
 ## Examples
     
-	use <util/fibseq.scad>;
+	use <util/fibseq.scad>
 	
 	echo(fibseq(1, 10));  // ECHO: [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]

docs/lib3x-find_index.md

@@ -11,6 +11,6 @@ Returns the index of the first element in the list that satisfies the testing fu
 
 ## Examples
 
-    use <util/find_index.scad>;
+    use <util/find_index.scad>
     
     assert(find_index([10, 20, 30, 40], function(e) e > 10) == 1);

docs/lib3x-flat.md

@@ -11,7 +11,7 @@ returns a new list with all sub-list elements concatenated into it recursively u
 
 ## Examples
 
-	use <util/flat.scad>;
+	use <util/flat.scad>
 
 	vt = [[[[1, 2], [3, 4]], [[5, 6], [7, 8]]]];
 

docs/lib3x-footprints2.md

@@ -11,8 +11,8 @@ Drive a turtle with `["forward", length]` or `["turn", angle]`. This function is
 
 ## Examples
 	    
-	use <polyline_join.scad>;
-	use <turtle/footprints2.scad>;
+	use <polyline_join.scad>
+	use <turtle/footprints2.scad>
 	
 	function arc_cmds(radius, angle, steps) = 
 		let(

docs/lib3x-footprints3.md

@@ -11,8 +11,8 @@ A 3D verion of [footprint2](https://openhome.cc/eGossip/OpenSCAD/lib3x-footprint
 
 ## Examples
 	    
-	use <polyline_join.scad>;
-	use <turtle/footprints3.scad>;
+	use <polyline_join.scad>
+	use <turtle/footprints3.scad>
 	
 	function xy_arc_cmds(radius, angle, steps) = 
 		let(

docs/lib3x-golden_spiral.md

@@ -13,7 +13,7 @@ It returns a vector of `[[x, y], angle]`.
 
 ## Examples
     
-	use <golden_spiral.scad>;
+	use <golden_spiral.scad>
 	        
 	pts_angles = golden_spiral(
 	    from = 3, 
@@ -28,7 +28,7 @@ It returns a vector of `[[x, y], angle]`.
 
 ![golden_spiral](images/lib3x-golden_spiral-1.JPG)
 	
-	use <golden_spiral.scad>;
+	use <golden_spiral.scad>
 	        
 	pts_angles = golden_spiral(
 	    from = 5, 

docs/lib3x-golden_spiral_extrude.md

@@ -17,7 +17,7 @@ When using this module, you should use points to represent the 2D shape. If your
 
 ## Examples
     
-	use <golden_spiral_extrude.scad>;
+	use <golden_spiral_extrude.scad>
 
 	shape_pts = [
 		[2, -10],
@@ -38,8 +38,8 @@ When using this module, you should use points to represent the 2D shape. If your
 
 ![golden_spiral_extrude](images/lib3x-golden_spiral_extrude-1.JPG)
 
-    use <shape_circle.scad>;
-	use <golden_spiral_extrude.scad>;
+    use <shape_circle.scad>
+	use <golden_spiral_extrude.scad>
 
 	$fn = 12;
 

docs/lib3x-has.md

@@ -12,9 +12,9 @@ If `lt` contains `elem`, this function returns `true`. If you want to test eleme
 
 ## Examples
 
-    use <voxel/vx_circle.scad>;
-    use <util/sort.scad>;
-    use <util/has.scad>;
+    use <voxel/vx_circle.scad>
+    use <util/sort.scad>
+    use <util/has.scad>
 
     pts = vx_circle(10);
     assert(has(pts, [2, -10])); 

docs/lib3x-hashmap.md

@@ -21,14 +21,14 @@ This function maps keys to values. You can use the following to process the retu
 
 ## Examples
 
-    use <util/map/hashmap.scad>;
-	use <util/map/hashmap_len.scad>;
-    use <util/map/hashmap_put.scad>;
-    use <util/map/hashmap_get.scad>;
-    use <util/map/hashmap_del.scad>;
-    use <util/map/hashmap_keys.scad>;
-    use <util/map/hashmap_values.scad>;
-	use <util/map/hashmap_entries.scad>;
+    use <util/map/hashmap.scad>
+	use <util/map/hashmap_len.scad>
+    use <util/map/hashmap_put.scad>
+    use <util/map/hashmap_get.scad>
+    use <util/map/hashmap_del.scad>
+    use <util/map/hashmap_keys.scad>
+    use <util/map/hashmap_values.scad>
+	use <util/map/hashmap_entries.scad>
 
     m1 = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
     assert(hashmap_len(m1) == 3);
@@ -45,8 +45,8 @@ This function maps keys to values. You can use the following to process the retu
 
 Want to simulate class-based OO in OpenSCAD? Here's my experiment.
 
-    use <util/map/hashmap.scad>;
-    use <util/map/hashmap_get.scad>;
+    use <util/map/hashmap.scad>
+    use <util/map/hashmap_get.scad>
 
     function methods(mths) = hashmap(mths);
     function _(name, instance) = hashmap_get(instance, name);

docs/lib3x-hashmap_del.md

@@ -13,9 +13,9 @@ This function deletes the mapping for the specified key from a [util/map/hashmap
 
 ## Examples
 
-    use <util/map/hashmap.scad>;
-    use <util/map/hashmap_get.scad>;
-    use <util/map/hashmap_del.scad>;
+    use <util/map/hashmap.scad>
+    use <util/map/hashmap_get.scad>
+    use <util/map/hashmap_del.scad>
 
     m1 = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
     m2 = hashmap_del(m1, "k1");

docs/lib3x-hashmap_entries.md

@@ -10,8 +10,8 @@ Returns a list containing all `[key, value]`s in a [util/map/hashmap](https://op
 
 ## Examples
 
-    use <util/map/hashmap.scad>;
-    use <util/map/hashmap_entries.scad>;
+    use <util/map/hashmap.scad>
+    use <util/map/hashmap_entries.scad>
 
     m = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
     echo(hashmap_entries(m));    // a list contains ["k1", 10], ["k2", 20], ["k3", 30]

docs/lib3x-hashmap_get.md

@@ -13,8 +13,8 @@ This function gets the value of the specified key from a [util/map/hashmap](http
 
 ## Examples
 
-    use <util/map/hashmap.scad>;
-    use <util/map/hashmap_get.scad>;
+    use <util/map/hashmap.scad>
+    use <util/map/hashmap_get.scad>
 
     m = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
     assert(hashmap_get(m, "k2") == 20);

docs/lib3x-hashmap_keys.md

@@ -10,8 +10,8 @@ Returns a list containing all keys in a [util/map/hashmap](https://openhome.cc/e
 
 ## Examples
 
-    use <util/map/hashmap.scad>;
-    use <util/map/hashmap_keys.scad>;
+    use <util/map/hashmap.scad>
+    use <util/map/hashmap_keys.scad>
 
     m = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
 

docs/lib3x-hashmap_len.md

@@ -10,8 +10,8 @@ Returns the length of a [util/map/hashmap](https://openhome.cc/eGossip/OpenSCAD/
 
 ## Examples
 
-    use <util/map/hashmap.scad>;
-	use <util/map/hashmap_len.scad>;
+    use <util/map/hashmap.scad>
+	use <util/map/hashmap_len.scad>
 
     m = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
     assert(hashmap_len(m) == 3);

docs/lib3x-hashmap_put.md

@@ -14,9 +14,9 @@ Puts a key/value pair to a [util/map/hashmap](https://openhome.cc/eGossip/OpenSC
 
 ## Examples
 
-    use <util/map/hashmap.scad>;
-    use <util/map/hashmap_put.scad>;
-    use <util/map/hashmap_get.scad>;
+    use <util/map/hashmap.scad>
+    use <util/map/hashmap_put.scad>
+    use <util/map/hashmap_get.scad>
 
     m1 = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
 

docs/lib3x-hashmap_values.md

@@ -10,8 +10,8 @@ Returns a list containing all values in a [util/map/hashmap](https://openhome.cc
 
 ## Examples
 
-    use <util/map/hashmap.scad>;
-    use <util/map/hashmap_values.scad>;
+    use <util/map/hashmap.scad>
+    use <util/map/hashmap_values.scad>
 
     m = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
 

docs/lib3x-hashset.md

@@ -19,12 +19,12 @@ This function models the mathematical set, backed by a hash table. You can use t
 
 ## Examples
 
-    use <util/set/hashset.scad>;
-    use <util/set/hashset_add.scad>;
-    use <util/set/hashset_has.scad>;
-    use <util/set/hashset_del.scad>;
-    use <util/set/hashset_len.scad>;
-    use <util/set/hashset_elems.scad>;
+    use <util/set/hashset.scad>
+    use <util/set/hashset_add.scad>
+    use <util/set/hashset_has.scad>
+    use <util/set/hashset_del.scad>
+    use <util/set/hashset_len.scad>
+    use <util/set/hashset_elems.scad>
 
     s1 = hashset([1, 2, 3, 4, 5, 2, 3, 5]);
     assert(hashset_len(s1) == 5);

docs/lib3x-hashset_add.md

@@ -13,9 +13,9 @@ This function adds an element to a [util/set/hashset](https://openhome.cc/eGossi
 
 ## Examples
 
-    use <util/set/hashset.scad>;
-    use <util/set/hashset_add.scad>;
-    use <util/set/hashset_has.scad>;
+    use <util/set/hashset.scad>
+    use <util/set/hashset_add.scad>
+    use <util/set/hashset_has.scad>
 
     s1 = hashset([1, 2, 3, 4, 5]);
     s2 = hashset_add(s1, 9);

docs/lib3x-hashset_del.md

@@ -13,9 +13,9 @@ This function dels an element from a [util/set/hashset](https://openhome.cc/eGos
 
 ## Examples
 
-    use <util/set/hashset.scad>;
-    use <util/set/hashset_del.scad>;
-    use <util/set/hashset_has.scad>;
+    use <util/set/hashset.scad>
+    use <util/set/hashset_del.scad>
+    use <util/set/hashset_has.scad>
 
     s1 = hashset([1, 2, 3, 4, 5]);
     s2 = hashset_del(s1, 3);

docs/lib3x-hashset_elems.md

@@ -10,8 +10,8 @@ Returns a list containing all elements in a [util/set/hashset](https://openhome.
 
 ## Examples
 
-    use <util/set/hashset.scad>;
-    use <util/set/hashset_elems.scad>;
+    use <util/set/hashset.scad>
+    use <util/set/hashset_elems.scad>
 
     s = hashset([1, 2, 3, 4, 5]);
     assert(hashset_elems(s) == [1, 2, 3, 4, 5]); 

docs/lib3x-hashset_has.md

@@ -13,8 +13,8 @@ Returns `true` if a [util/set/hashset](https://openhome.cc/eGossip/OpenSCAD/lib3
 
 ## Examples
 
-    use <util/set/hashset.scad>;
-    use <util/set/hashset_has.scad>;
+    use <util/set/hashset.scad>
+    use <util/set/hashset_has.scad>
 
     s = hashset([1, 2, 3, 4, 5]);
     assert(hashset_has(s, 3));

docs/lib3x-hashset_len.md

@@ -10,8 +10,8 @@ Returns the length of the elements in a [util/set/hashset](https://openhome.cc/e
 
 ## Examples
 
-    use <util/set/hashset.scad>;
-    use <util/set/hashset_len.scad>;
+    use <util/set/hashset.scad>
+    use <util/set/hashset_len.scad>
 
     s = hashset([1, 2, 3, 4, 5]);
     assert(hashset_len(s) == 5);

docs/lib3x-helix.md

@@ -13,8 +13,8 @@ Gets all points on the path of a spiral around a cylinder. Its `$fa`, `$fs` and
 
 ## Examples
     
-	use <helix.scad>;
-	use <polyline_join.scad>;
+	use <helix.scad>
+	use <polyline_join.scad>
 	
 	$fn = 12;
 	
@@ -36,8 +36,8 @@ Gets all points on the path of a spiral around a cylinder. Its `$fa`, `$fs` and
 
 ![helix](images/lib3x-helix-1.JPG)
 
-	use <helix.scad>;
-	use <polyline_join.scad>;
+	use <helix.scad>
+	use <polyline_join.scad>
 
 	$fn = 12;
 

docs/lib3x-helix_extrude.md

@@ -21,7 +21,7 @@ Its `$fa`, `$fs` and `$fn` parameters are consistent with the `cylinder` module.
 
 ## Examples
     
-	use <helix_extrude.scad>;
+	use <helix_extrude.scad>
 
 	shape_pts = [
 		[5, -2],
@@ -43,7 +43,7 @@ Its `$fa`, `$fs` and `$fn` parameters are consistent with the `cylinder` module.
 
 ![helix_extrude](images/lib3x-helix_extrude-1.JPG)
 
-	use <helix_extrude.scad>;
+	use <helix_extrude.scad>
 
 	r1 = 40;
 	r2 = 20;

docs/lib3x-hexagons.md

@@ -10,7 +10,7 @@ This module creates hexagons in a hexagon.
 
 ## Examples
 
-	use <hexagons.scad>;
+	use <hexagons.scad>
 	
 	radius = 20;
 	spacing = 2;
@@ -20,7 +20,7 @@ This module creates hexagons in a hexagon.
 
 ![hexagons](images/lib3x-hexagons-1.JPG)
 
-	use <hexagons.scad>;
+	use <hexagons.scad>
 	
 	radius = 20;
 	spacing = 2;

docs/lib3x-hollow_out.md

@@ -8,7 +8,7 @@ Hollows out a 2D object.
 
 ## Examples
 
-    use <hollow_out.scad>;
+    use <hollow_out.scad>
 
 	hollow_out(shell_thickness = 1) 
         circle(r = 3, $fn = 48);

docs/lib3x-in_polyline.md

@@ -12,7 +12,7 @@ Checks whether a point is on a line.
 
 ## Examples
 
-    use <in_polyline.scad>;
+    use <in_polyline.scad>
 
     pts = [
         [0, 0],
@@ -27,7 +27,7 @@ Checks whether a point is on a line.
 
 ----
 
-    use <in_polyline.scad>;
+    use <in_polyline.scad>
 
     pts = [
         [10, 0, 10],

docs/lib3x-in_shape.md

@@ -13,8 +13,8 @@ Checks whether a point is inside a shape.
 
 ## Examples
 
-    use <shape_taiwan.scad>;
-    use <in_shape.scad>;
+    use <shape_taiwan.scad>
+    use <in_shape.scad>
 
     points = shape_taiwan(30);
 

docs/lib3x-joint_T.md

@@ -17,7 +17,7 @@ Create a joint_T for rotatable models.
 
 ## Examples
 
-	use <part/joint_T.scad>;
+	use <part/joint_T.scad>
 
 	$fn = 48;
 

docs/lib3x-lerp.md

@@ -12,6 +12,6 @@ Linear interpolate the vector v1 to v2.
 
 ## Examples
 
-    use <util/lerp.scad>;
+    use <util/lerp.scad>
     
     assert(lerp([0, 0, 0], [100, 100, 100], 0.5) == [50, 50, 50]);  

docs/lib3x-line2d.md

@@ -13,7 +13,7 @@ Creates a line from two points. When the end points are `CAP_ROUND`, you can use
 
 ## Examples
 
-    use <line2d.scad>;
+    use <line2d.scad>
     
     $fn = 24;
 

docs/lib3x-line3d.md

@@ -13,7 +13,7 @@ Creates a 3D line from two points.
 
 ## Examples
 
-    use <line3d.scad>;
+    use <line3d.scad>
     
 	line3d(
 	    p1 = [0, 0, 0], 
@@ -24,7 +24,7 @@ Creates a 3D line from two points.
 
 ![line3d](images/lib3x-line3d-1.JPG)
 
-    use <line3d.scad>;
+    use <line3d.scad>
 	
 	line3d(
 	    p1 = [0, 0, 0], 
@@ -37,7 +37,7 @@ Creates a 3D line from two points.
 
 ![line3d](images/lib3x-line3d-2.JPG)
 			   
-    use <line3d.scad>;
+    use <line3d.scad>
     
     line3d(
         p1 = [0, 0, 0], 

docs/lib3x-lines_intersection.md

@@ -13,7 +13,7 @@ Find the intersection of two line segments. Return `[]` if lines don't intersect
 
 ## Examples
 
-    use <lines_intersection.scad>;
+    use <lines_intersection.scad>
 
     line1 = [[0, 0], [0, 10]];
     line2 = [[5, 0], [-5, 5]];

docs/lib3x-loft.md

@@ -11,10 +11,10 @@ When having uniform cross sections, you can use [sweep](https://openhome.cc/eGos
 
 ## Examples
 
-	use <shape_star.scad>;
-	use <shape_circle.scad>;
-	use <ptf/ptf_rotate.scad>;
-	use <loft.scad>;
+	use <shape_star.scad>
+	use <shape_circle.scad>
+	use <ptf/ptf_rotate.scad>
+	use <loft.scad>
 		
 	sects = [
 		for(i = 10; i >= 4; i = i - 1)

docs/lib3x-lsystem2.md

@@ -23,13 +23,14 @@
 - `start` : The starting point of the turtle. Default to `[0, 0]`.
 - `forward_chars` : Chars used for forwarding after the last iteration. Default to `'F'`. 
 - `rule_prs` : The probabilities for taking rules. If each rule is chosen with a certain probability, it's a stochastic L-system. Each probability value for a rule ranges from 0 to 1.
+- `seed` : Optional. Seed value for random number generator for repeatable results. **Since:** 3.3.
 
 ## Examples
 
 [lsystem2-collections.scad](https://github.com/JustinSDK/dotSCAD/blob/master/examples/turtle/lsystem2_collection.scad) collects several L-system grammars. Here's one of them.
 
-	use <turtle/lsystem2.scad>;
-	use <line2d.scad>;
+	use <turtle/lsystem2.scad>
+	use <line2d.scad>
 
 	for(line = fern()) {
 		line2d(
@@ -56,8 +57,8 @@
 
     // a stochastic L-system
 
-	use <turtle/lsystem2.scad>;
-	use <line2d.scad>;
+	use <turtle/lsystem2.scad>
+	use <line2d.scad>
 
 	for(line = weed()) {
 		line2d(

docs/lib3x-lsystem3.md

@@ -27,13 +27,14 @@
 - `start` : The starting point of the turtle. Default to `[0, 0]`.
 - `forward_chars` : Chars used for forwarding after the last iteration. Default to `'F'`. 
 - `rule_prs` : The probabilities for taking rules. If each rule is chosen with a certain probability, it's a stochastic L-system. Each probability value for a rule ranges from 0 to 1.
+- `seed` : Optional. Seed value for random number generator for repeatable results. **Since:** 3.3.
 
 ## Examples
 
 [lsystem3-collections.scad](https://github.com/JustinSDK/dotSCAD/blob/master/examples/turtle/lsystem3_collection.scad) collects several L-system grammars. Here's one of them.
 
-	use <turtle/lsystem3.scad>;
-	use <polyline_join.scad>;
+	use <turtle/lsystem3.scad>
+	use <polyline_join.scad>
 
 	for(line = hilbert_curve()) {
 		polyline_join([line[0], line[1]])
@@ -56,8 +57,8 @@
 
     // a stochastic L-system
 
-	use <turtle/lsystem3.scad>;
-	use <polyline_join.scad>;
+	use <turtle/lsystem3.scad>
+	use <polyline_join.scad>
 
 	for(line = vine()) {
 		polyline_join([line[0], line[1]])

docs/lib3x-m_determinant.md

@@ -10,7 +10,7 @@ It can calculate a determinant, a special number that can be calculated from a s
 
 ## Examples
 
-    use <matrix/m_determinant.scad>;
+    use <matrix/m_determinant.scad>
 
     assert(
         m_determinant([

docs/lib3x-m_mirror.md

@@ -10,7 +10,7 @@ Generate a 4x4 transformation matrix which can pass into `multmatrix` to mirror
 
 ## Examples
 
-	use <matrix/m_mirror.scad>;
+	use <matrix/m_mirror.scad>
 
 	rotate([0, 0, 10]) 
 		cube([3, 2, 1]);

docs/lib3x-m_replace.md

@@ -0,0 +1,32 @@
+# m_replace
+
+It replaces the aᵢⱼ element of a matrix.
+
+**Since:** 3.3
+
+## Parameters
+
+- `m` : A matrix.
+- `i` : The i-th row.
+- `j` : The j-th column.
+- `value` : The new value.
+
+## Examples
+
+    use <matrix/m_replace.scad>
+
+    original_m = [
+        [1, 2, 3, 4],
+        [5, 6, 7, 8],
+        [9, 10, 11, 12]
+    ];
+
+    expected = [
+        [1, 2, 3, 4],
+        [5, 6, 70, 8],
+        [9, 10, 11, 12]
+    ];
+
+    actual = m_replace(original_m, 1, 2, 70);
+
+    assert(actual == expected);

docs/lib3x-m_rotation.md

@@ -11,7 +11,7 @@ Generate a 4x4 transformation matrix which can pass into `multmatrix` to rotate
 
 ## Examples
 
-	use <matrix/m_rotation.scad>;
+	use <matrix/m_rotation.scad>
 
 	point = [20, 0, 0];
 	a = [0, -45, 45];
@@ -25,7 +25,7 @@ Generate a 4x4 transformation matrix which can pass into `multmatrix` to rotate
 
 ![m_rotation](images/lib3x-m_rotation-1.JPG)
 
-	use <matrix/m_rotation.scad>;
+	use <matrix/m_rotation.scad>
 
 	v = [10, 10, 10];
 

docs/lib3x-m_scaling.md

@@ -10,7 +10,7 @@ Generate a 4x4 transformation matrix which can pass into `multmatrix` to scale i
 
 ## Examples
 
-	use <matrix/m_scaling.scad>;
+	use <matrix/m_scaling.scad>
 
 	cube(10);
 	translate([15, 0, 0]) 

docs/lib3x-m_shearing.md

@@ -12,7 +12,7 @@ Generate a 4x4 transformation matrix which can pass into `multmatrix` to shear a
 
 ## Examples
 
-	use <matrix/m_shearing.scad>;
+	use <matrix/m_shearing.scad>
 
 	color("red") {
 		multmatrix(m_shearing(sx = [1, 0]))

docs/lib3x-m_translation.md

@@ -10,7 +10,7 @@ Generate a 4x4 transformation matrix which can pass into `multmatrix` to transla
 
 ## Examples
 
-	use <matrix/m_translation.scad>;
+	use <matrix/m_translation.scad>
 
 	cube(2, center = true); 
 	multmatrix(m_translation([5, 0, 0]))

docs/lib3x-m_transpose.md

@@ -10,7 +10,7 @@ It transposes a matrix.
 
 ## Examples
 
-    use <matrix/m_transpose.scad>;
+    use <matrix/m_transpose.scad>
 
     original_m = [
         [1, 2, 3, 4],

docs/lib3x-midpt_smooth.md

@@ -12,9 +12,9 @@ Given a 2D path, this function constructs a mid-point smoothed version by joinin
 
 ## Examples
 
-    use <polyline_join.scad>;
-    use <shape_taiwan.scad>;
-    use <midpt_smooth.scad>;
+    use <polyline_join.scad>
+    use <shape_taiwan.scad>
+    use <midpt_smooth.scad>
 
     taiwan = shape_taiwan(50);  
     smoothed = midpt_smooth(taiwan, 20, true);

docs/lib3x-multi_line_text.md

@@ -9,7 +9,7 @@ Creates multi-line text from a list of strings. Parameters are the same as the b
 
 ## Examples
     
-	use <multi_line_text.scad>;
+	use <multi_line_text.scad>
 
 	multi_line_text(
 		["Welcome", "to", "Taiwan"],

docs/lib3x-mz_hamiltonian.md

@@ -9,12 +9,13 @@ Creates a hamiltonian path from a maze. The path is the result of maze traversal
 - `rows` : The rows of a maze.
 - `columns` : The columns of a maze.
 - `start` : The start point to travel the maze. Default to `[0, 0]`.
+- `init_cells` : You can define your own initial cell data, a 2-dimension list of `[x, y, type, visited]`. `visited` means the cell is visited or not. A visited cell won't be visited when traveling the maze. If you don't provide `init_cells`, `mz_square` will generate one automatically. If you provide `init_cells`, `rows` and `columns` will be ignored. **Since:** 3.3
 - `seed` : The maze is traveling randomly. Use `seed` to initialize the pseudorandom number generator.
 
 ## Examples
     
-    use <maze/mz_hamiltonian.scad>;
-    use <polyline_join.scad>;
+    use <maze/mz_hamiltonian.scad>
+    use <polyline_join.scad>
 
     rows = 5;
     columns = 10;

docs/lib3x-mz_hex_walls.md

@@ -15,9 +15,9 @@ It's a helper for creating wall data from maze cells. You can transform wall poi
 
 ## Examples
     
-	use <maze/mz_square_cells.scad>;
-	use <maze/mz_hex_walls.scad>;
-	use <polyline_join.scad>;
+	use <maze/mz_square_cells.scad>
+	use <maze/mz_hex_walls.scad>
+	use <polyline_join.scad>
 
 	rows = 10;
 	columns = 12;

docs/lib3x-mz_hexwalls.md

@@ -0,0 +1,33 @@
+# mz_hexwalls
+
+It's a helper for creating wall data from maze cells. You can transform wall points for creating different types of mazes.
+
+**Since:** 3.3
+
+## Parameters
+
+- `cells` : Maze cells.
+- `cell_radius` : The radius of a cell.
+- `left_border` : Default to `true`. Create the leftmost border of the maze.
+- `bottom_border` : Default to `true`. Create the bottommost border of the maze.
+
+## Examples
+    
+	use <maze/mz_square.scad>
+	use <maze/mz_hexwalls.scad>
+	use <polyline_join.scad>
+
+	rows = 10;
+	columns = 12;
+	cell_width = 5;
+	wall_thickness = 2;
+
+	cells = mz_square(rows, columns);
+	walls = mz_hexwalls(cells, cell_width);
+
+	for(wall = walls) {
+		polyline_join(wall) 
+		    circle(wall_thickness, $fn = 24);
+	}
+	
+![mz_hexwalls](images/lib3x-mz_hexwalls-1.JPG)

docs/lib3x-mz_square.md

@@ -0,0 +1,61 @@
+# mz_square
+
+This function returns cell data of a square maze. The data is a 2-dimension list of cells. A cell has the data structure `[x, y, type]`. `x` and `y` are 0-based. `x` means the x-th column and `y` means y-th row for a cell. The value of `type` can be `0`, `1`, `2`, `3` or `4`. Setting them to constants is convenient.
+
+	NO_WALL = 0;          // the cell has no wall
+	TOP_WALL = 1;         // the cell has a top wall
+	RIGHT_WALL = 2;       // the cell has a right wall
+	TOP_RIGHT_WALL = 3;   // the cell has a top wall and a right wall
+	MASK = 4;             // the cell is masked.
+
+The cell data is seperated from views. You can use cell data to construct [different types of mazes](https://www.thingiverse.com/justinsdk/collections/maze-generator).
+
+**Since:** 3.3
+
+## Parameters
+
+- `rows` : The number of rows.
+- `columns` : The number of columns.
+- `start` : The start point to travel the maze. Default to `[0, 0]`.
+- `init_cells` : You can define your own initial cell data, a 2-dimension list of `[x, y, type, visited]`. `visited` means the cell is visited or not. A visited cell won't be visited when traveling the maze. If you don't provide `init_cells`, `mz_square` will generate one automatically. If you provide `init_cells`, `rows` and `columns` will be ignored.
+- `x_wrapping` : Default to `false`. If you want to wrap the maze in the x direction, set it to `true`. The last column of cells will be adjacent to the first column of cells.
+- `y_wrapping` : Default to `false`. If you want to wrap the maze in the y direction, set it to `true`. The last row of cells will be adjacent to the first row of cells.
+- `seed` : The maze is traveling randomly. Use `seed` to initialize the pseudorandom number generator.
+
+## Examples
+    
+	use <maze/mz_square.scad>
+	use <line2d.scad>
+
+	rows = 10;
+	columns = 10;
+	cell_width = 5;
+	wall_thickness = 2;
+
+	NO_WALL = 0;       
+	TOP_WALL = 1;    
+	RIGHT_WALL = 2;    
+	TOP_RIGHT_WALL = 3; 
+	MASK = 4;
+
+	cells = mz_square(rows, columns);
+
+	for(row = cells, cell = row) {
+		type = cell[2];
+		
+		translate([cell.x, cell.y] * cell_width) {
+			if(type == TOP_WALL || type == TOP_RIGHT_WALL) {
+				line2d([0, cell_width], [cell_width, cell_width], wall_thickness);
+			}
+			
+			if(type == RIGHT_WALL || type == TOP_RIGHT_WALL) {
+				line2d([cell_width, cell_width], [cell_width, 0], wall_thickness);
+			}	
+		}
+	}
+
+	line2d([0, 0], [cell_width * columns, 0], wall_thickness);
+	line2d([0, 0], [0, cell_width * rows], wall_thickness);
+
+![mz_square](images/lib3x-mz_square-1.JPG)
+

docs/lib3x-mz_square_cells.md

@@ -24,8 +24,8 @@ The cell data is seperated from views. You can use cell data to construct [diffe
 
 ## Examples
     
-	use <maze/mz_square_cells.scad>;
-	use <line2d.scad>;
+	use <maze/mz_square_cells.scad>
+	use <line2d.scad>
 
 	rows = 10;
 	columns = 10;