glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	glPushMatrix();
	glLoadIdentity();

	// ... do some translation ...

	drawCube();

	glPopMatrix();

	glPushMatrix();
	glLoadIdentity();

	// ... do some translation ...

	glBegin(GL_QUADS);

	// Use a dark gray background and set transparency.
	glColor4f(1.0, 1.0, 1.0, .5);

	glVertex3f(-1.0, +1.0, 0.0); // top left
	glVertex3f(-1.0, -1.0, 0.0); // bottom left
	glVertex3f(+1.0, -1.0, 0.0); // bottom right
	glVertex3f(+1.0, +1.0, 0.0); // top right
	glEnd();

	glPopMatrix();

	// ... swap the buffers ...