Create a [Voronoi diagram](https://en.wikipedia.org/wiki/Voronoi_diagram) in the first quadrant. You specify a space and a grid width. The center of each cell will be distributed in each grid randomly.
-`size` : 2 value array [x, y], rectangle with dimensions x and y.
-`grid_w` : The width of each grid. If it can split `size` equally, the voronoi diagram is seamless at the junction of top-bottom and left-right.
-`seed` : Seed value for random number generator for repeatable results.
-`spacing` : Distance between cells. Default to 1.
-`r`, `delta`, `chamfer` : The outlines of each cell can be moved outward or inward. These parameters have the same effect as [`offset`](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Transformations#offset).
-`region_type` : The initial shape for each cell can be `"square"` or `"circle"`. Default to `"square"`.