add doc

README.md

@@ -247,7 +247,7 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 
 ### Maze
 
-- mz_square_blocks
+- [mz_square_blocks](https://openhome.cc/eGossip/OpenSCAD/lib2x-mz_square_blocks.html)
 - mz_square_get
 - mz_square_initialize
 - mz_square_walls

docs/lib2x-mz_square_cells.md

@@ -0,0 +1,63 @@
+# mz_square_cells
+
+This function returns cell data of a square-based maze. The data is a list of cells. A cell has the data structure `[x, y, type, visited]`. `x` and `y` are 0-based. `x` means 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;       
+	TOP_WALL = 1;    
+	RIGHT_WALL = 2;    
+	TOP_RIGHT_WALL = 3; 
+	MASK = 4;
+
+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:** 2.5
+
+## 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 list of `[x, y, type, visited]`s. `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_cells` will generate one automatically.
+- `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_cells.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_cells(rows, columns);
+
+	for(cell = cells) {
+		x = cell[0];
+		y = cell[1];
+		type = cell[2];
+		
+		translate([x, 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 * rows, 0], wall_thickness);
+	line2d([0, 0], [0, cell_width * columns], wall_thickness);
+
+![mz_square_cells](images/lib2x-mz_square_cells-1.JPG)
+

src/maze/mz_square_cells.scad

@@ -1,9 +1,19 @@
+/**
+* mz_square_cells.scad
+*
+* @copyright Justin Lin, 2020
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib2x-mz_square_cells.html
+*
+**/
+
 use <_impl/_mz_cells_impl.scad>;
 use <mz_square_initialize.scad>;
 
 function mz_square_cells(rows, columns, start = [0, 0], init_cells, x_wrapping = false, y_wrapping = false, seed) = 
     go_maze( 
-        start[0], start[1],   // starting point
+        start[0], start[1],   
         is_undef(init_cells) ? mz_square_initialize(rows, columns) : init_cells,  
         rows, columns, x_wrapping, y_wrapping, seed
     );