What do parallel lines look like?

Hint: The parallel lines never intersect with each other. They always maintain the same distance between the corresponding points. Angle made by the parallel lines is zero degrees.

Complete step by step solution:
 When we are talking about the parallel lines, the first thing we should say is that they look the same. We must say that there is only one trait which can violate the above statement. And that trait is the length. It means that the straight lines are parallel if they do not meet at any point, even if they are of different length. We can try and extend the parallel lines to confirm if they intersect with each other at any point. But the fact is that our efforts will remain worthless. Therefore, it is certain that the distance between the corresponding points of the parallel lines is always the same.
  Another important point to be noted is that the angle made by the parallel lines is always zero degree. Since they do not intersect with each other, they do not make angles between them.
Consider the lines ${{l}_{1}}$ and ${{l}_{2}}.$
Suppose the length of the line ${{l}_{1}}=4cm.$
And the length of the line ${{l}_{2}}=6cm.$
We say, if these two lines make an angle of zero degree, then they are parallel, regardless of their lengths.
Not only two, but any number of lines in a plane can be parallel if they satisfy the above given properties of parallel lines.
Also, we can say, a line $l$ is parallel to itself. This property is called reflexivity.
Suppose that a line ${{l}_{1}}$ is parallel to a line ${{l}_{2}}.$ Then ${{l}_{2}}$ is also parallel to ${{l}_{1}}.$ This property is called symmetry.
Also, suppose that a line ${{l}_{1}}$ is parallel to a line ${{l}_{2}}$ and ${{l}_{2}}$ is parallel to another line ${{l}_{3}}.$ Then, the line ${{l}_{1}}$ is parallel to the line ${{l}_{3}}.$ This property is called transitivity.

Note: We use the symbol $\parallel $ to denote the parallel lines. Suppose that ${{l}_{1}}$ and ${{l}_{2}}$ are parallel lines. Then we write, ${{l}_{1}}\parallel {{l}_{2}}.$ If ${{l}_{1}},{{l}_{2}}$ and ${{l}_{3}}$ are three parallel lines, then we write ${{l}_{1}}\parallel {{l}_{2}}\parallel {{l}_{3}}.$ The railway track which never intersect with each other is an example of parallel lines.