Gif 1
How to Create an Ellipse![Gif of How to Make an Ellipse](images/how-to-create-an-ellipse-animation-of-locus-and-focus.gif)
The larger the $ |a|$ is, the more the graphs narrows.
The larger the $ |a|$ is, the more narrow the parabola is. Or, another way to think of it, the closer that the value of $a$ gets to zero, the wider the parabola becomes.