Stephen,

I didn't think Tomas's #3 was called for in this problem.
Did you intend it to be one of the restrictions?

Stan,

I like your sorting procedure to get a line divided in color. When I re-read the problem I see that it is actually a solution since it doesn't say that there need to be a separation between the groups. So you can do your procedure left and right instead of front and back and they will be sorted as they arrive.

You da man, as usual.

/Tomas

"Da Man" has it!

There is nothing to restrict anybody from moving about, so Stan's solution is valid. The only thing is (and it is a minor niggle) how "side" is defined. Stan's solution splits them front and back, and the head gnome wanted them each side. However, I don't think the Head Gnome will be too fussed about that minor detail

Anyway, that was the solution I was after - are there any other methods of sorting you good people can come up with?

*coughs* Since they are allowed to move around I think both the Odd/Even count and the time consuming version works. They can then start the sorting and observations once at the meeting. Both procedures are definitely overkill for this problem though.

/Tomas