Opening upwards, the doors evoke the image of a seagull's wings. In French they are portes papillon (butterfly doors). The papillon door, slightly different in its architecture from a gullwing door – which Jean Bugatti designed in 1939, fourteen years before Mercedes-Benz produced its similar, famous 300SL gullwing door – is a pre-cursor, but is often overlooked when discussing "Gull-wing" design. Conventional car doors are typically hinged at the front-facing edge of the door and the door swings outward in a horizontal plane.