Answer: It is called Media
Explanation:
The answer is the horizon line.
Shading is showing the objects' roundness or shape; shade is the blocking of a light source; and shadow is the variation between black and white with the darkest part at the center and the 'shadow' fades at the edges.
Even if your heels fit perfectly, if you try running in them, they're probably going to slip off. Now that's with regular heels, so imagine that with slippery glass heels.