My words when I first saw that lol. I think these are prototype hair designs for Nanami, and that Mutsumi's hairstyle was later based on one of Nanami's scrapped hair designs.
I remember I found this on one review on Zigsow.jp. Sadly, I can't put here the source and artist, because Zigsow has been down for me for a long time (I get ERR_ADDRESS_INVALID when I try to access it).
I remember I found this on one review on Zigsow.jp. Sadly, I can't put here the source and artist, because Zigsow has been down for me for a long time (I get ERR_ADDRESS_INVALID when I try to access it).