Ursus-Veritas' post below about the recycled tree and the third Doctor's car in the preview for next week's episode has me wondering. What other shout-outs to previous Doctors and companions have we seen this year?

Off the top of my head I can come up with:

  • Four's scarf in Clara's hallway
  • Artie reading Amelia Williams' book
  • The talk about the umbrella stand
  • The Doctor mentioning going to Akhaten with his granddaughter
  • The wolf and the rose in the opening title sequence

One also has to wonder how many of these are going somewhere (like the "continuity error" of the Doctor's jacket in season five), how many are red herrings and how many are just fan-service for the 50th anniversary.