Doctor Who Series 10: 13 Easter Eggs & References You Might've Missed In 'The Pilot'
8. Miss Quill's Blackboard
When the Doctor is explaining his unique perspective on quantum mechanics to his university students ("Time and Relative Dimension in Space. It means life"), we see him writing on a blackboard that has a white border adorned with distinctive TARDIS-like roundels.
Eagle-eyed fans might recognise this as the same prop used in spin-off show Class. It can be seen in Miss Quill's science class at Coal Hill Academy.
The fate of Class is currently hanging in the balance, so it might not bode well for the show that the BBC is already redistributing its props...