Cubo españó

#include <GL/glut.h>
#include <GL/gl.h>

void reshape(int width, int height){
    glViewport(0,0,width,height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-1, 1, -1, 1, -1, 1);
    glMatrixMode(GL_MODELVIEW);
}

void display(){
    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(1.0f, 0.0f, 0.0f);
    glLoadIdentity();
    glBegin(GL_QUADS);
      glVertex3f(-0.5f,0.5f,0.0f);
      glVertex3f(0.5f,0.5f,0.0f);
      glVertex3f(0.5f,-0.5f,0.0f);
      glVertex3f(-0.5f,-0.5f,0.0f);

      glVertex3f(-1.0f,1.0f,0.0f);
      glVertex3f(0.0f,1.0f,0.0f);
      glVertex3f(0.0f,0.0f,0.0f);
      glVertex3f(-1.0f,0.0f,0.0f);

      glColor3f(1.0f,1.0f,0.0f);

      glVertex3f(-1.0f,1.0f,0.0f);
      glVertex3f(-0.5f,0.5f,0.0f);
      glVertex3f(-0.5f,-0.5f,0.0f);
      glVertex3f(-1.0f,0.0f,0.0f);

      glVertex3f(0.0f,1.0f,0.0f);
      glVertex3f(0.5f,0.5f,0.0f);
      glVertex3f(0.5f,-0.5f,0.0f);
      glVertex3f(0.0f,0.0f,0.0f);

      glColor3f(1.0f,0.0f,0.0f);

      glVertex3f(-0.5f,0.5f,0.0f);
      glVertex3f(0.5f,0.5f,0.0f);
      glVertex3f(0.5f,-0.5f,0.0f);
      glVertex3f(-0.5f,-0.5f,0.0f);
    glEnd();
    glFlush();
}

void init(){
    glClearColor(0,0,0,0);
}

int main(int argc, char **argv){
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowPosition(50,50);
    glutInitWindowSize(500,500);
    glutCreateWindow("CUBO");
    init();
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutMainLoop();
    return 0;
}