public int[][] getRegularPolygon(int vertices,int rotation, int size){
        // returns a list of vertices describing a regular polygon
        // with n vertices, rotated by (rotation) degrees.
        // The polygon fits into a rectangle [xTopLeft,yTopLeft,width, height]=[0,0,size,size],
        // input: vertices: number of vertices
        //        rotation: angle of rotation in degrees
        //        size: size of bounding square, i.e. all coordinates returned
        //              are in [0,size]
        // output: 2 dimensional array V of vertex coordinates, v[][0]=x,V[][1]=y 
        
        double  [][]p=new double[vertices][2];
        int     [][]V=new int[vertices][2];
        
        // The basic regular polygon
        double degDiff=360.0/(vertices-1);
        for (int i=0; i <vertices; i++){
            double deg = i*360.0/(vertices);
            deg=deg/180*Math.PI;
            p[i][0]=Math.cos(deg);
            p[i][1]=Math.sin(deg);
        }
        
        // Rotation, Scaling and Transformation
        double a=rotation*Math.PI/180.0;
        double cs=Math.cos(a);
        double sn=Math.sin(a);
        for (int i=0; i <vertices; i++){
            V[i][0]=(int)Math.round((cs*p[i][0]-sn*p[i][1])*size/2+size/2);
            V[i][1]=(int)Math.round((sn*p[i][0]+cs*p[i][1])*size/2+size/2);
        }
        return V;
    }