HURR DURR I LIKE TO COLOR
Don't ask me to explain Souji and Yosuke's ridiculous couch.
I'm going to assume that they found an abandoned, flea infested sofa by the side of the road and took it home. One decision to let Nanako pick the fabric they'd reupholster it with and two hours of Kanji and a badass staple gun later, this is what they were left with. Yosuke named it The Artist Formerly Known As Couch.
...I'm going to stop talking now.