Last September graphic designer and computer animator Billy Hanshaw uploaded onto Youtube a
as a demo to show off his animation skills.
Mr. Hanshaw's animation takes an Escher-inspired symbolic approach, showing turning gears in a clock, an infinitely spiraling clock face, and the Seal of Rassilon melting off the Doctor's pocket watch.
Steven Moffat spotted it and liked it so much he arranged with the artist to base the new season's credits on it.