Volumetric cube plots

The following examples show how to use cubes.

The first simple example shows the basic usage of cubes. The first example shows 2 by 2 by 2 cubes and each cube is assigned a color. The opacity is set to 0.05 (and can be changed using the context menu).

The second example is more practical, showing 128 by 128 by 128 cubes. The color varies with x while the opacity is determined from a simple test whether or not a cube lies within a sphere (see source code of this file for details).