After you've had a good look at the images, I'll explain what the refraction index does in light bending. A transparent block hovering in front of a tiled surface at some distance. The environment is black . You'll also see the refraction of light rays on the top and side faces of the block. In figure 2.2 you see a block with refraction index 1.
Rays pass right through it.
In this case our eye will see a piece of the green block through the front surface. Try to figure out what you will see in the top surface. 2.3 High refraction Figure 2.3 shows a highly refractive block . The refraction is so high that we see the bottom surface of the block squashed to just a strip. Try to figure out what you will see in this top surface.