Sir, - a couple of weeks ago I forked out £45.95 for a dark blue shirt and a tie with a yellow background. It now appears that every office worker in Dublin has done the same. In order to reduce embarrassing clashes at the workplace, can I suggest the following.Office workers with the surname initials A-M should dress in their blue shirts and yellow ties on Monday, Tuesday, or Wednesday, while those with initials N-Z wear theirs Thursday or Friday.Thanking you in anticipation of your co-operation. - Yours, etc., John Devlin, Erne Terrace, Dublin 2.