For example, at EAS 2002, those who attended the "apiary workshops" could see that Cornell uses sets of 4 square tiles, with each square tile painted a different color.  The 4 tiles are themselves arranged into a larger square. --- Given that each square is no more than a 2 or 3 inches across, I'd conclude that they are useless

Response:
Are you referring to the squares on the sides of the bee houses? If so, there are two on each of the four sides of the bee house, making 8 total per house. The house is 8x8 feet, so you have 2 12" squares on a background 8x8 feet. The house itself is painted, one is yellow, one green, one blue and one white.

Now I figure the bees find the correct house and remember which side is theirs, north, east west or south. So assuming they are approaching the north side they have only to choose which of two squares is their entrance.

Now I don't know about bees, but I can see clearly at several hundred feet that one square is red with three horizontal yellow stripes and the other is blue with a white dot. But even if they can't make it out until they are 20 or 30 feet close, they have only to decide whether to land on the left one or the right one. Incidently, one is a little higher than the other, adding to the identity of the two ports.

Personally, I would say they would have no trouble distinguishing which entrance is theirs without the colors, but the point here is to minimize drifting. Most drifting occurs during the initial orientation flights when young bees fly out and attempt to memorize the appearance of their home. At this point a 12" red square with yellow bars looks very different from a blue one with a white circle.

We spent a lot of time choosing the size, pattern and color and it was not for nothing. We use paired squares, one with 3 bars and one with a circle. The colors include yellow, green, blue, white and red in various shades. The red appears black to them, I know, but I like red myself so I use it.

pb