add mobius_maze

examples/mobius_maze.scad

@@ -0,0 +1,26 @@
+include <hull_polyline3d.scad>;
+include <rotate_p.scad>;
+include <square_maze.scad>;
+
+rows = 48;
+columns = 8;
+block_width = 2;
+wall_thickness = 1;   
+angle = 180;
+// $fn = 24;
+
+leng = rows * block_width;
+radius = 0.5 * leng / PI;
+a_step = 360 / leng;
+
+blocks = go_maze( 
+    1, 1,   // starting point
+    starting_maze(rows, columns),  
+    rows, columns, y_circular = true
+);
+walls = maze_walls(blocks, rows, columns, block_width, bottom_border = false);
+
+for(wall_pts = y_twist(walls, angle, rows, columns, block_width)) {  
+   z_rotated = [for(pt = wall_pts) rotate_p([radius + pt[0], 0, pt[2]], a_step * pt[1])];
+   hull_polyline3d(z_rotated, wall_thickness);
+}