Beyond tentacles and underpants, the Japanese have an interesting fascination with the vagina—so much so that they must pixelate it. The pixelation has become so fine, however, that Mosaic Porn is an art form and cultural institution in itself: We know what we're looking at but at least the Japanese can save face by saying it has been digitally obfuscated.
http://gramponante.com/japanese-porn-exporters-put-their-money-where-the-mosaic-is/
http://gramponante.com/japanese-porn-exporters-put-their-money-where-the-mosaic-is/