In the Knife of Dreams epilogue...

NOTE - I also talk about the Gathering Storm prologue and future developments in the body of this post

Perava and a handful of red sisters arrive at the Black Tower with an intention to bond Asha'man as warders.

Perava, specifically, notes that the decor is all red and black.

In the prologue of The Gathering Storm, I can't recall which one specifically, but one of the female Forsaken comments on the red and black decor that Moridin has chosen as his style.

Is this designed to connect the dots that Taim has gone over to the shadow?

Logain had warned Rand about Taim, but I can't recall any of the books explicitly stating that Taim, in fact, has betrayed Rand (even though most readers expected this for quite a while).