Guinea Bissau Flag using openGL

#include<windows.h>
#include<GL/glut.h>
void Draw()
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(0,255,0);
glBegin(GL_QUADS);
glVertex2d(20.0,10.0);
glVertex2d(20.0,-10.0);
glVertex2d(-20.0,-10.0);
glVertex2d(-20.0,10.0);

glColor3f(255, 255, 0);
glBegin(GL_QUADS);
glVertex2d(20.0,10.0);
glVertex2d(20.0,0.0);
glVertex2d(-20.0,0.0);
glVertex2d(-20.0,10.0);

glColor3f(255, 0, 0);
glBegin(GL_QUADS);
glVertex2d(-8.0,10.0);
glVertex2d(-8.0,-10.0);
glVertex2d(-20.0,-10.0);
glVertex2d(-20.0,10.0);
glEnd();

glColor3f(0,0,0);

//Triangle_1
glBegin(GL_TRIANGLES);
glVertex3f(-17.7f, 1, 0);
glVertex3f(-15.4f, 1.0f, 0);
glVertex3f(-16.0, -0.8f, 0);
glEnd();

//Triangle_2
glBegin(GL_TRIANGLES);
glVertex3f(-15.4f, 1.0f, 0);
glVertex3f(-13.8, 1, 0);
glVertex3f(-14.6, 4, 0);
glEnd();

//Triangle_3
glBegin(GL_TRIANGLES);
glVertex3f(-13.8, 1, 0);
glVertex3f(-11.5, 1, 0);
glVertex3f(-13.2, -0.8, 0);
glEnd();

//Triangle_4
glBegin(GL_TRIANGLES);
glVertex3f(-13.2, -0.8, 0);
glVertex3f(-15, -1, 0);
glVertex3f(-12.9, -3.6, 0);
glEnd();

//Triangle_5
glBegin(GL_TRIANGLES);
glVertex3f(-16.0, -0.8f, 0);
glVertex3f(-14.2, -1, 0);
glVertex3f(-16.2, -3.6, 0);
glEnd();

//Polygon
glBegin(GL_POLYGON);
glVertex3f(-15.4f, 1.0f, 0);
glVertex3f(-13.8, 1, 0);
glVertex3f(-13.2, -0.8, 0);
glVertex3f(-14.6, -1.3, 0);
glVertex3f(-16.0, -0.8f, 0);
glEnd();

glFlush();
}

void Initialize()
{
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-25.0, 25.0, -25.0, 25.0, -25.0, 25.0);
}
int main(int Argc, char** Argv)
{
glutInit(&Argc, Argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize(500,500);
glutInitWindowPosition(300,300);
glutCreateWindow("Guinea Bissau(19103108)");
Initialize();
glutDisplayFunc(Draw);
glutMainLoop();
return 0;
}