Example: Drawing 2 Point Ellipse / 3 Point Ellipses

Hi all,

Recently wrote a piece of code for a friend to draw 2 point Ellipse and 3 point Ellipse. To this date, Grasshopper default functions has only one method to define an ellipse by an axis and the major and minor radius. It does not have a way to specify two points and the distance sum to the two points as parameter. 

So I made some conversion to do that:

Since my friend is trying to model drawing ellipse by a string, the length input is based on the length of string loop, not the distance sum. Look at the following image and you will understand:

Similarly, I have also modeled what would happen if there are three pins with one string loop. Result is a shape that consist of 6 ellipse segments. The reason of this is not too obvious, there are basically 2 cases: the string are taut between one side of the triangle, or the string is taut between 2 sides.