Quote Originally Posted by Serapy View Post
You can only move forward or backward at a time.
Which does nothing to counter the fact that you can move forwards in a counter clockwise manner, or backwards in a counter clockwise manner.

These pictures / animations show that they are moving forward or backward at a time.
The animation shows those symbols aren't moving, but even if we assume their movement as indicative of movement, the shortest rotation required to go from one symbol to the other when viewing in a left to right manner, the standard manner for eye charts, would be clockwise.