text:  The <unk> on the cloud was achieved through a mix of fog on the studio floor and post @-@ production special effects . Director Saul <unk> explained that it was difficult to achieve the desired look for the <unk> ; the first ones he likened to <unk> from Rainbow which was too " cute " of an appearance , and so the effects team created more menacing CGI faces . <unk> 's introduction to the <unk> introduced two novel effects for the show . The first was a single @-@ shot camera tracking from a few feet away from the <unk> to its interior , with the implication of the <unk> 's trans @-@ dimensional nature shown to the audience . In the following shot , the camera does a complete circle of the <unk> console , an effect not seen since the early days of the show . <unk> wanted to include this shot to further emphasize the " bigger on the inside than the outside " nature of the time machine . 
  