Made an Eccentricity Graph that shows the transition from circle, through ellipse to hyperbola.

Only problem is at e=1 which is theoretically a parabola, but comes out as rubbish (I made it a line to cover up the problem) ... any suggestions?

I want people to easily see how the conic-sections are related to e.

Code for "a" and "b":

if (e < 1) {
    a = 1;
    b = Math.sqrt(( 1-e*e)*a*a);
} else {
    a = 1;
    b = Math.sqrt((-1+e*e)*a*a);
}

Which is then plotted by this code (in a loop with "t" going from 0 to 3):

if (e < 1) {
    xVal = a * Math.cos(t);
    yVal = b * Math.sin(t); 
} else if (e==1) {
    xVal = t;
    yVal = 0; 
} else {
    xVal = a / Math.cos(t);
    yVal = b * Math.tan(t); 
}