We all know that eyes are quite common, and even the combination or red and blue, or being told to remember things.

But in two episodes in this series we've had female characters concealing themselves between facial masks (incidentally, neither of them seeming to need anything to fix them to). Does anyone think that masks are a recurring image, either physically or metaphorically?

Liz 10 wore a mask, the Daleks attempted to hide their true natures, the Venetian vampires wore perception filters, and Anaya also wear a literal mask.

Okay, so monsters in Who are always trying to hide their intentions and forms, so that's a stretch. But they all seem to be using perception filters - perhaps the high-tech version of a mask?

When they say that silence will fall - is silence just the mask that hides something more terrible?

Good idea but no...I think masks are a common Who trait!

As you say perhaps not masks but the more encompassing theme of hidden identities.

Add to the list Prisoner Zero and the Angels masquerading (sorry) as Aplan statues.

What's the meaning behind it ?

With Liz 10 the fact she didn't need anything to attach it to was a plot point - the very old, antique mask that was perfectly moulded to her features was a clue to her being very old herself, as it couldn't have been made for anyone else...

The Silurian/Eocine/Homo Reptilian had a crenellated face that could easily have a mask moulded to fit between the crenellations, thereby making it easy to take off and put back on should it be needed in war (as she was clearly of the warrior caste).

What I noticed about them was the fact that they were fixed masks, yet Liz 10 could still move her jaw about to talk (despite the plot point of it needing to fit to her face exactly to stay on), and Alaya could shoot her prehensile tongue out through no hole!

But I do like where you're going with that theory - I felt the same about the silence. The silence was a portent to something much more sinister...