Code to draw an ellipse is very like the code for a rectangle.
The important difference is that the position
of the ellipse is at its centre.
(The position of a rectangle is its top-left corner.)
ellipse(right, down, width, height);
The first two numbers set the position inside the canvas.
The second two numbers set the size of the ellipse.
ellipse(100, 60, 120, 80);