Watching them a bit attentively, I realized that some butterflies have a pattern that resemble some specific songs. I went ahead to tag the ones I was able to recognize. :)

Also, I'm not good creating notes so I'll just leave the image like that, sorry about that.

Gotaru said:

Watching them a bit attentively, I realized that some butterflies have a pattern that resemble some specific songs. I went ahead to tag the ones I was able to recognize. :)

Also, I'm not good creating notes so I'll just leave the image like that, sorry about that.

Good eye! The Author confirms it on the Pixiv page as well. I'd wager a guess the one in the center is Hajimete no Oto, from the sunrise, but that and the upper right one are tricky tricky.