There are 19 different wing designs that Vivillon can have on its wings. It ranges mainly in color and style based on what region that 3DS is registered/set. From each area, it differs based on the region's climate, continent and even the top most popular countries on Earth.
Vivillon has the second widest variety of obtainable Pokémon Forms, having a total of 19. It is bested by Unown, which has 28 forms. (Arceus, using type plates and its Multitype ability, also has 19 forms; however, one of its forms, the ???-type form, is regarded as unobtainable, causing it to only have 18 obtainable forms.)
Vivillon's name comes from "vivi", which is translated as "lively" and "papillon", which is "butterfly".