question: private static List < Vector2D > buildQuadrilateral ( final Vector2D ... points ) { List < Vector2D > quadrilateral = new ArrayList < Vector2D > ( ) ; for ( Vector2D p : points ) { if ( ! quadrilateral . contains ( p ) ) { quadrilateral . add ( p ) ; } } return quadrilateral ; }
target:  Build the convex quadrilateral with the found corner points (with min/max x/y coordinates).