As the arms move along the circular path, they essentially can arrive in four distinct locations:
The only thing the arms will do is either stay put, or travel to an adjacent location.
Like analog videotape, we can fast-forward or rewind, but we cannot skip frames or jump around. If the arm is at the In-High location, we know it will either travel to In-Low or Out-High, or else stay where it is.
There is great simplicity to the arm movements this way.
It’s similar to counting the sequence of numbers:
1 2 3 4 5 6 7 8 9
9 8 7 6 5 4 3 2 1
but never 1 2 8 …
nor 9 8 5 …
The arms simply honor the integrity of the sequence of the circle.
There is no great mystery, just the clarity of sequence and movement from and to an adjacent location.