Let a=b for values 1, 2, and 3:

Well, we still get circles for our case a=b, however, these aren't your normal, run-of-the-mill circles. Let's compare this to the cases a<b and a>b for values 1, 2, 3, and 4. Before we see how these graphs look, I am conjecturing that they will be ellipses where a<b yields a vertical major axis ans a>b yields a horizontal major axisd. Let's see:

a<b:

a>b:

Again, my conjectures were correct. So far we see the pattern forming for the cases a=b, a<b, and a>b. We get graphs of circles, vertical ellipses, and horizontal ellipses, respectively.