Since you didn't include the picture i could be wrong but the most famous 'study of a woman's back' i know of is matisse.
It is because flash mobs is a group of people dancing to music and music is art.
i may be able to help but id need to find a way to like- talk talk to you so i can get more information, this is a familiar anime but id need a weeeeee bit more info
the ability of creating fine works of art like drawing, painting, sculpting, composition of music,etc is called art skill
hope it helps
