This is not a crop circle, and it is not the work of aliens. This is a paddy-field of rice in Japan.
This romantic rice field is in Yamagata prefecture, showing the 16th-century samurai Naoe Kanetsugu and his wife, Osen.
So how do they do it? (This rice has not been painted)
Different varieties of rice have differently coloured blades. The farmer has chosen three varieties, one green, one a creamy-white, and another a purple colour. Then he carefully plants the seedlings in order to create this natural crop art.