An iconic image. A white table (like Tsukumizu's one, see tkmiz/who is tkmiz/room), on the table is an iMac. A white mug with a pink stripe (cute) is near the keyboard. The keyboard doesn't look like a Magic one.
Sis is sitting on the chair (look at the fish hairpin and the lab coat), with some things spinning around her (10 of them). Maybe the thing is Yocchan?
Theory. These brownhaired girls are Sis' depressive memories. Which ones? I don't know, but she's definitely not feeling good.