Sorry, yeah, it's confusing.
Both clock faces can be taped to their "timeline" strip so that the clock and the letters on the strip are both facing right side up or the clock is facing up and the letters are upside down.
So there are four combinations of orientation:
And then alternating:
The present clock face is up while its letters are down, while the past clock face is up as well as its letters UP-DOWN/UP-UP
And then the opposite. UP-UP/UP-DOWN
I fear I have not made this any clearer.
And may be completely wrong.
Did I mention I like books?