Comment 2 for bug 157588

After more testing, I've a simpler and more complete pattern.

ctrlaltleft and ctrlaltright always move 2 faces

except:
when moving off the left (left of zero), the face is set to last face
when moving off the right of the last face, the face is set to face 0.

except if I press keys too quickly.

This fits all tested cases. Forget the bit about last-key-but-one.

Why does the cube rotate by 2 faces instead of 1?
Why does the cube rotate by odd numbers of faces when I press the keys too fast?