Here are some pictures of the Incremental Convex Hull
The First Picture shows the most basic convex hull of 3 points:
The second picture shows that when points are clicked inside the convex hull it does not change since it is not part of the convex hull:
Now we add points to the outer edge to expand the convex hull:
Now we add in points even further out to make some of the points of the current convex hull invalid:
