#include <stdio.h> 
#include <GL/glut.h> 
void display(void) 
{ 
 glClear( GL_COLOR_BUFFER_BIT); 
 glColor3f(0.0, 1.0, 0.0); 
 glBegin(GL_POLYGON); 
  glVertex3f(2.0, 4.0, 0.0); 
  glVertex3f(8.0, 4.0, 0.0); 
  glVertex3f(8.0, 6.0, 0.0); 
  glVertex3f(2.0, 6.0, 0.0); 
 glEnd(); 
 glFlush(); 
} 

int main(int argc, char **argv) 
{ 
 printf("hello world\n"); 
 glutInit(&argc, argv); 
 glutInitDisplayMode ( GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH); 

 glutInitWindowPosition(100,100); 
 glutInitWindowSize(300,300); 
 glutCreateWindow ("square"); 

 glClearColor(0.0, 0.0, 0.0, 0.0); 
 glMatrixMode(GL_PROJECTION); 
 glLoadIdentity(); 
 glOrtho(0.0, 10.0, 0.0, 10.0, -1.0, 1.0); 

 glutDisplayFunc(display); 
 glutMainLoop(); 

 return 0; 
}
