Tip: Orthographic view of 3D graphics

The orthographic view of the 3D plot can be generated by using ViewPoint option. It comes very handy in some situations.

data = RandomReal[1, {20, 3}];
ListPlot3D[data, InterpolationOrder -> 0, ColorFunction -> "Rainbow", Mesh -> None, Boxed -> True, Axes -> None]
Add option ViewPoint->{0,0,Infinity} and draw it again.

Then we can put together a nice bounded Voronoi diagram. It saves the trouble to use BoundedDiagram from Computational Geometry Package.