static void draw_minus(void)
{
 glVertex3f(-.10,-.005,0);
 glVertex3f(-.10, .005,0);
 glVertex3f(-.01, .005,0);
 glVertex3f(-.01,-.005,0);
}

static void draw_plus(void)
{
 glVertex3f(-.10,-.005,0);
 glVertex3f(-.10, .005,0);
 glVertex3f(-.01, .005,0);
 glVertex3f(-.01,-.005,0);
 glVertex3f(-.05,-.045,0);
 glVertex3f(-.06,-.045,0);
 glVertex3f(-.06, .045,0);
 glVertex3f(-.05, .045,0);
}

static void draw_z(void)
{
 glVertex3f( .01, .15,0);
 glVertex3f( .10, .15,0);
 glVertex3f( .09, .14,0);
 glVertex3f( .01, .14,0);
 glVertex3f( .10, .15,0);
 glVertex3f( .02,-.15,0);
 glVertex3f( .01,-.15,0);
 glVertex3f( .09, .15,0);
 glVertex3f( .01,-.15,0);
 glVertex3f( .02,-.14,0);
 glVertex3f( .10,-.14,0);
 glVertex3f( .10,-.15,0);
}

static void draw_y(void)
{
 glVertex3f( .01, .15,0);
 glVertex3f( .04, .03,0);
 glVertex3f( .05, .03,0);
 glVertex3f( .02, .15,0);
 glVertex3f( .10, .15,0);
 glVertex3f( .05, .03,0);
 glVertex3f( .04, .03,0);
 glVertex3f( .09, .15,0);
 glVertex3f( .04, .04,0);
 glVertex3f( .04,-.15,0);
 glVertex3f( .05,-.15,0);
 glVertex3f( .05, .04,0);
}

static void draw_x(void)
{
 glVertex3f( .01, .15,0);
 glVertex3f( .02, .15,0);
 glVertex3f( .10,-.15,0);
 glVertex3f( .09,-.15,0);
 glVertex3f( .09, .15,0);
 glVertex3f( .10, .15,0);
 glVertex3f( .02,-.15,0);
 glVertex3f( .01,-.15,0);
}

static void draw_mz(void)
{
 glBegin(GL_QUADS);
 draw_minus();
 draw_z();
 glEnd();
}

static void draw_pz(void)
{
 glBegin(GL_QUADS);
 draw_plus();
 draw_z();
 glEnd();
}

static void draw_my(void)
{
 glBegin(GL_QUADS);
 draw_minus();
 draw_y();
 glEnd();
}

static void draw_py(void)
{
 glBegin(GL_QUADS);
 draw_plus();
 draw_y();
 glEnd();
}

static void draw_mx(void)
{
 glBegin(GL_QUADS);
 draw_minus();
 draw_x();
 glEnd();
}

static void draw_px(void)
{
 glBegin(GL_QUADS);
 draw_plus();
 draw_x();
 glEnd();
}

static void draw_box(void)
{
 int i;
 int j;

 glBegin(GL_LINES);
 for (i=-1;i<=1;i+=2)
  { for (j=-1;j<=1;j+=2)
     { glVertex3f(i,j,-1);
       glVertex3f(i,j, 1);
       glVertex3f(j,-1,i);
       glVertex3f(j, 1,i);
       glVertex3f(-1,i,j);
       glVertex3f( 1,i,j);
     }
  }
 glEnd();
}

static void render(void)
{
 glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
 glLoadIdentity();
 glRotatef(t*.2,1,1,1);
 glRotatef(t*.03,1,0,0);
 glColor3f(.5,.5,.5);
 glPushMatrix();
 glTranslatef(0,0,-1);
 draw_mz();
 glPopMatrix();
 glPushMatrix();
 glTranslatef(0,0,1);
 draw_pz();
 glPopMatrix();
 glPushMatrix();
 glTranslatef(0,-1,0);
 glRotatef(90,0,1,0);
 glRotatef(-90,1,0,0);
 draw_my();
 glPopMatrix();
 glPushMatrix();
 glTranslatef(0,1,0);
 glRotatef(90,0,1,0);
 glRotatef(-90,1,0,0);
 draw_py();
 glPopMatrix();
 glPushMatrix();
 glTranslatef(-1,0,0);
 glRotatef(90,0,0,1);
 glRotatef(-90,1,0,0);
 draw_mx();
 glPopMatrix();
 glPushMatrix();
 glTranslatef(1,0,0);
 glRotatef(90,0,0,1);
 glRotatef(-90,1,0,0);
 draw_px();
 glPopMatrix();
 glColor3f(1,1,1);
 draw_box();
 SDL_GL_SwapBuffers();
 glFinish();
}