Theory:

Have you ever observed the vegetable cuttings? What shape does the cut portion of the vegetable resemble?
 
Silimarly, have you noticed your shadow that falls on the ground when you are under the sun? If you are standing in the same position throughout the day, how will your shadow look when the sun rises, at noon and when the sun sets?
 
The answers to all these questions depends on how we view a solid.
There are three different ways to view a solid:
 
1. Cutting and slicing a solid
 
2. Shadow play
 
3. Looking at solids from different angles
Cutting and slicing a solid
Cutting the objects horizontally or vertically will result in cross section of the object.
 
What is a cross-section?
A cross-section is the new face of the object we get when we slice the object from any direction. The newly formed face will always resemble a two-dimensional shape.
Example:
Now, let us try to cut a cuboid both horizontally and vertically.
 
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