How to draw an ellipse in codeworld haskell given co-ordinates

Question

I need to draw an ellipse given two co-ordinates

Ellipse Coords
        Coords

but i'm not sure how to do this with vertices, co-vertices, foci, and a centre point. I'm basically confused as to which points go into the two co-ordinates. I have this so far

Ellipse (a, b)(c, d)       = scaled(solidCircle(1) (???)
Circle (a, b)(c, d)        = (solidCircle (r))
                                            where xc = ((c-a)*(c-a))
                                                  yc = ((d-b)*(d-b))
                                                   r = sqrt(xc +yc)

I included the circle equation as I'm using scaled circle.

Thank you!