This is a custom block that I created for others to use and learn from. It uses sine/cosine functions to draw ellipses according to your specifications. This technique was also employed in: https://scratch.mit.edu/projects/96949485/ and https://scratch.mit.edu/projects/70736016/ .
Look inside if you want the block. Feel free to use it. I would prefer to be credited but I won't be angry if you forget. AMERICANS PLEASE NOTE: I use the British spelling of words such as: customisable (customizable), and centre (center). This is not incorrect where I live, but you may want to make sure you spell correctly at work, or at school.