Drag the dots around.
So the purpose for this is that it can detect if a quadrilateral is concave (meaning that one vertex is more than 180 degrees), then it means that a point is inside a big triangle made only by three of the points of the quadrilateral. In a later project I will explain it more visually... Oh, and I use three inequalities for this project, and for the mouse, if it is in a place that all three inequalities are satisfied, then it is in the triangle. 7/22/15: Corrected a bug for vertical lines in the triangle
