See the common feature?
Now, let's try to combine the variables:
This is a vertical line x=2.
This is a vertical ellipse centered at the origin with vertices at (0,3) and (0,-3), and endpoints of minor axis at (2,0) and (-2,0).
This is a sine function with magnitude 2.
This is an object in 3-dimension.
You see, parametric equations can form a lot of curve with different type:
a) function, non-function;
b) line, curve;
c) 2-D, 3-D;
Can you try to build one set of parametric equations and figure out the graph of the set of equations?