Question: What does the Doctor mean at the end of the episode about changing the colours of the ships or spaceships from green to white? Is this a reference to an earlier episode or something else?
Doctor Who (1963)
1 question in season 17

Visible crew/equipment: (Ep. 2) When The Doctor, Jo, and Dr. Tyler are taken into Omega's palace, in the first shot of the multiple passageways (right before Jo says that it looks like Aladdin's cave) the curved chalk actor's mark is visible on the floor, then we see it again in three following shots. Note that when they're all escorted further inside, just as Dr. Tyler comments about the matter/anti-matter not making sense, Jon Pertwee looks down, presumably to make sure he hits his mark.
Castrovalva - S19-E1
The Doctor: That's the trouble with regeneration, you never quite know what you're going to get. (00:12:15)
Trivia: This Doctor Who story was originally scripted and produced as a four-episode story, but, just two weeks before transmission, upon viewing the story, co-creators Sydney Newman and Donald Wilson felt that the final two episodes (Episode 3, 'Crisis'; and Episode 4, 'The Urge to Live') should be combined into a single episode. The new 'condensed' episode incorporated the opening titles of 'Crisis' with the closing credits of 'The Urge to Live'.





Chosen answer: In the original legend of the Minotaur, Theseus' ship was supposed to approach Athens with white sails if he had slain the creature, or black sails if he had been killed. Although he killed the Minotaur, he forgot to change the sails to white and his father, King Aegeus, killed himself in despair. Two stories earlier ("The Creature from the Pit"), the Doctor claimed to have been involved in the original legend and said he had forgotten to remind Theseus about the sails.
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