public static extern IntPtr CreateEllipticRgn(int nLeftRect, int nTopRect,int nRightRect, int nBottomRect);

            IntPtr r1 = CreateEllipticRgn(0,0,300,300);

            IntPtr r2 = CreateEllipticRgn(100,100,300,300);

            IntPtr r3= CreateEllipticRgn(100,100,300,300);

static extern IntPtr CreateEllipticRgn(int nLeftRect, int nTopRect,

Public Function CreateEllipticRgn(ByVal X1 As Integer, ByVal Y1 As Integer, ByVal X2 As Integer, ByVal Y2 As Integer) As Integer