@DougS: People are sensitive to polarization of light
People with normal vision can see the Haidinger figures. Even the degree of polarization of the blue sky 90° from the Sun is enough to see it, if you know what to look for.
Re orientation in general:
Alice asked the Cheshire Cat "Would you tell me, please, which way I ought to go from here?" "That dependes a good deal on where you want to get to," said the Cat. "I don't much care where --" said Alice. "Then it doesn't matter which way you go," said the Cat. "--so long as I get somewhere," Alice added. "Oh, you 're sure to do that," said the Cat, "if you only walk long enough."
Biting the hand that feeds IT
