Gradient’s parameters:

The parameters of the violet sphere:
Blending Options>Gradient Overlay

Gradient’s parameters:

The parameters of the grey sphere:
Blending Options>Gradient Overlay

Gradient’s parameters:

Now we shall copy each sphere. We need to make four copies of the blue sphere, three copies of the red one, nine copies of the green sphere, three copies of the violet one, two copies for the grey sphere and three copies of the orange one. The layers may be placed on your own wish.

Merge down in a group all the copies, the way we described earlier the merging down method. The group’s Opacity should be situated on 80%.