Block 1:
   glPolygonMode(GL_FRONT, GL_LINE);
   glPolygonMode(GL_BACK, GL_FILL);
   glBegin(GL_POLYGON);
      glVertex3f(20.0, 20.0, 0.0);
      glVertex3f(80.0, 20.0, 0.0);
      glVertex3f(80.0, 80.0, 0.0);
      glVertex3f(20.0, 80.0, 0.0);
   glEnd();

Block 2:
   glPolygonMode(GL_FRONT, GL_LINE);
   glPolygonMode(GL_BACK, GL_FILL);
   glBegin(GL_POLYGON);
      glVertex3f(20.0, 80.0, 0.0);
      glVertex3f(20.0, 20.0, 0.0);
      glVertex3f(80.0, 20.0, 0.0);
      glVertex3f(80.0, 80.0, 0.0);
   glEnd();

Block 3:
   glPolygonMode(GL_FRONT, GL_LINE);
   glPolygonMode(GL_BACK, GL_FILL);
   glBegin(GL_POLYGON);
      glVertex3f(80.0, 80.0, 0.0);
      glVertex3f(80.0, 20.0, 0.0);
      glVertex3f(20.0, 20.0, 0.0);
      glVertex3f(20.0, 80.0, 0.0);
   glEnd();

Block 4:
   glFrontFace(GL_CW);
   glPolygonMode(GL_FRONT, GL_LINE);
   glPolygonMode(GL_BACK, GL_FILL);
   glBegin(GL_TRIANGLES);
      glVertex3f(80.0, 10.0, -1.0);
      glVertex3f(90.0, 75.0, 1.0);
      glVertex3f(15.0, 10.0, 0.5);
   glEnd();

Block 5:
   glPolygonMode(GL_FRONT, GL_LINE);
   glPolygonMode(GL_BACK, GL_FILL);
   glBegin(GL_TRIANGLES);
      // CCW
      glVertex3f(20.0, 80.0, 0.0);
      glVertex3f(20.0, 20.0, 0.0);
      glVertex3f(50.0, 80.0, 0.0);

      //CCW
      glVertex3f(50.0, 80.0, 0.0);
      glVertex3f(20.0, 20.0, 0.0);
      glVertex3f(50.0, 20.0, 0.0);

      // CW
      glVertex3f(50.0, 20.0, 0.0);
      glVertex3f(50.0, 80.0, 0.0);
      glVertex3f(80.0, 80.0, 0.0);

      // CCW
      glVertex3f(80.0, 80.0, 0.0);
      glVertex3f(50.0, 20.0, 0.0);
      glVertex3f(80.0, 20.0, 0.0);
   glEnd();

Block 6:
   glPolygonMode(GL_FRONT, GL_LINE);
   glPolygonMode(GL_BACK, GL_FILL);
   glBegin(GL_TRIANGLE_STRIP);
      glVertex3f(20.0, 80.0, 0.0);
      glVertex3f(20.0, 20.0, 0.0);
      glVertex3f(50.0, 80.0, 0.0);
      glVertex3f(50.0, 20.0, 0.0);
      glVertex3f(80.0, 80.0, 0.0);
      glVertex3f(80.0, 20.0, 0.0);
   glEnd();