A partially transparent version of the cube
The cube that you see in Figure 5 is the same cube that you saw in Figure 1. But:
Figure 1 shows the 3D axes belonging to the cube.
Figure 5 shows the 3D axes belonging to the grouned.
The cube in Figure 1 is 100% opaque.
The cube in Figure 5 is only 50% opaque.
This makes it possible to see the 3D axes belonging to the ground showing through the cube.
(The cube in Figure 5 is 50-percent transparent. Opacity and transparency are the reverse of one another.)