The mark consists of : Vertical metal lightpole of square constant cross-section welded concentrically to a side-aligned wider-square horizontal metal baseplate, with a chosen engagement pattern including four substantially vertical baseplate portions upbent through upwardly-curving smooth baseplate curves into isosceles triangles secured respectively against the four lightpole walls and terminating in upwardly-extending points to create a crown-like appearance. Four mounting openings near the baseplate corners are not part of the mark; also, only a baseplate-adjacent portion of the vertical lightpole is shown.