Sir, - Desmond Bennett (March 7th) is right. The PVC window, ideally in an old building, is a national institution which concisely represents our outstanding lack of visual awareness. Our national symbol is not, of course, the outdated shamrock, but a plastic shopping bag fluttering from a tree or, where appropriate, adding a splash of colour to the river bank. - Yours, etc., T.C.F. Doorley, Rushbrooke, Cobh, Co Cork.