GrBitMap *base=GrNew(grbase2);

void DrawIt()
{
  ClearWindowText;
  base->pen_width=2;
  base->color=GR_RED;
  GrLine3(base,-100,-100,-100, -100, 100,-100);
  GrLine3(base,-100, 100,-100,	100, 100,-100);
  GrLine3(base, 100, 100,-100,	100,-100,-100);
  GrLine3(base, 100,-100,-100, -100,-100,-100);

  GrLine3(base,-100,-100, 100, -100, 100, 100);
  GrLine3(base,-100, 100, 100,	100, 100, 100);
  GrLine3(base, 100, 100, 100,	100,-100, 100);
  GrLine3(base, 100,-100, 100, -100,-100, 100);

  GrLine3(base,-100,-100, 100, -100,-100,-100);
  GrLine3(base,-100, 100, 100, -100, 100,-100);
  GrLine3(base, 100, 100, 100,	100, 100,-100);
  GrLine3(base, 100,-100, 100,	100,-100,-100);
}

void Box()
{
  double theta=0,phi=0,zeta=0,s=1,s1=1.05;
  I8 *r1,*r2,*r3,*r4,*r5;
  U8 sc,ch;
  U4 *old_update_window=Fs->update_window;
  Fs->update_window=&DrawIt;

  base->x=200;
  base->y=200;
  base->flags|=BMF_TRANSFORMATION;
  while (TRUE) {
    if (ScanChar(&sc,&ch)) break;
    r1=GrTheta(theta);
    r2=GrPhi(phi);
    r3=GrTheta(zeta);
    r4=GrMulMat(r1,r2);
    r5=GrMulMat(r4,r3);
    Free(base->r);
    base->r=GrScaleMat(r5,s);
    Free(r1);
    Free(r2);
    Free(r3);
    Free(r4);
    Free(r5);

    Sleep(60);
    theta+=pi2/70;
    phi  +=pi2/90;
    zeta +=pi2/110;
    s *=s1;
    if (s<0.2|| s>1.4) s1=1/s1;
  }
  Fs->update_window=old_update_window;
}

Box;