Image black empty images

//Opencv Code for Spiral Effect

#include <opencv2/core/core.hpp>

#include <opencv2/highgui/highgui.hpp>

using namespace cv;

int main( )

{

 // Create black empty images

 Mat image = Mat::zeros( 500, 500, CV_8UC3 );

 //Factor by which u need to increase the radius

 int x=5;



 for(int i=x;i<=250;i=i+x)

 {

  if(i%(2*x)==0){

 // Draw a ellipse

 ellipse( image, Point( 250+x, 250 ), Size( i, i ), 180, 180, 0, Scalar( 0, 255,255 ), 2, 8 );

 imshow("Image",image);

 waitKey( 100 );

  }

  else

  {

 ellipse( image, Point( 250, 250 ), Size( i, i ), 0, 0, 180, Scalar( 0, 255,255 ), 2, 8 );

 imshow("Image",image);

 waitKey( 100 );



  }

 }

 waitKey( 0 );



 return(0);

}