function change(direction){
    old = current;
    if((direction > 0) && ((current+direction) <= num_elements))
      current += direction;
    else if((direction < 0) && ((current+direction) >= 0))
      current += direction;
      
    if(old != current){
      if(direction >= 1){
        $('duk_text_'+current).style.left = 450 +'px';
        $('duk_text_'+current).style.top = -400 +'px';
        $('duk_image_'+current).style.left = 0 +'px';
        $('duk_image_'+current).style.top = -400 +'px';
        $('duk_image_'+current).show();
        $('duk_text_'+current).show();
        new Effect.Move('duk_text_'+old, {x: 450,  y: 400, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.6 });
        new Effect.Move('duk_image_'+old, {x: 0,  y: 400, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.1 });
        new Effect.Move('duk_text_'+current, {x: 450,  y: 0, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.6 });
        new Effect.Move('duk_image_'+current, {x: 0,  y: 0, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.1 });
      }else{
        $('duk_text_'+current).style.left = 450 +'px';
        $('duk_text_'+current).style.top = 400 +'px';
        $('duk_image_'+current).style.left = 0 +'px';
        $('duk_image_'+current).style.top = 400 +'px';
        new Effect.Move('duk_text_'+old, {x: 450,  y: -400, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.6 });
        new Effect.Move('duk_image_'+old, {x: 0,  y: -400, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.1 });
        new Effect.Move('duk_text_'+current, {x: 450,  y: 0, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.6 });
        new Effect.Move('duk_image_'+current, {x: 0,  y: 0, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.1 });

      }

      new Effect.Move('duk_menu', {x: 0,  y: 100-100*current, mode: 'absolute', transition: Effect.Transitions.sinoidal, duration: 1.1 });

    }

  }