Doctor Who Series 12: 10 Huge Questions After Orphan 55
9. Have We Seen Those Cubes Before?
Some eagle-eyed viewers were speculating before the episode had aired that the glowing cube Graham was seen holding in the TARDIS was a hypercube. Though referenced multiple times in officially licenced books and audio adventures, these Gallifreyan objects (also known as tesseracts) only appear on-screen in two episodes.
In The War Games, the second Doctor builds one using six flat white squares and his extra-sensory mind powers. They are a means of communicating with fellow Time Lords across time and space. Largely forgotten ever since, Steven Moffat brought them back in Neil Gaiman’s The Doctor’s Wife to tease and frustrate the return of the Doctor’s kind.
Graham’s device, though also constructed from a series of flat squares, is of a completely different origin and function. The teleportation cube, like the time ring or the vortex manipulator is an effective way of taking out the TARDIS as an easy escape route. So many Doctor Who stories, especially the base under siege variety, could have been over in minutes if the Doctor rounded everyone up and took them off in the TARDIS.