A visual phenomenon . . .

Our community does a nice job decorating for the holidays. Most of the entrances have feature huge evergreen trees that they drape with hundreds of colored lights--red, blue, green and orange.

I've noticed this in the past. Tonight, however, I did a little experiment.

When I'm at a distance from the trees, all the lights appear to be oblong, with the red and orange lights oriented vertically and the blue and green lights oriented horizontally. Moreover, the red and blue lights both appear slightly longer than the orange and green lights.

The impression is really quite stunning. But when I get up close, the aspect ratios disappear and I can see that the lights are all basically round.

The elongation is an optical illusion.

And tonight I did an experiment: I tilted my head 90 degrees to the right and, sure enough, the blue and green lights then appeared to be elongated in a vertical position and the red and orange flipped to a horizontal aspect.

--Any ideas concerning why I would see such phenomena?

Do you have that kind of experience?