(b) Any assembly of two lamps marked "D", whether identical or not, having the same function, [DEL] or a3c0
(b) Any assembly of two independent lamps, whether identical or not, having the same function, both approved as type "D" lamp and installed so that the projection of their apparent surfaces in the direction of the reference axis occupies not less than 60 per cent of the smallest quadrilateral circumscribing the projections of the said apparent surfaces in the direction of the reference axis. a0c0