Now your eye is pointing forward again, in the same
direction as it was when it started. But notice where
the dark side is now compared to where it was at first.
Before the dark side was on the bottom. Compared to
before, the eye is on its side. It has violated Donders'
law.
If you try the same three rotations again the eye will
end up upside down in the head. This is can be painful!
Granted, these are big rotations and normally the eye
cannot turn by much more than 45 deg. from center
But since the eye makes saccades a few times each
second, a bad choice of axis can quickly lead to this
problem even when the saccades are small.
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