Shinobu, pointing to the wall: What color is this?
Tanjiro: Gray.
Zenitsu: Grey.
Shinobu, turning to Inosuke: Now tell him what color you think it is.
Inosuke: Dark white.
i have no idea where i'm going with this, but lets hope it's good. warning: swearing, a bit of manga spoilers... More
Shinobu, pointing to the wall: What color is this?
Tanjiro: Gray.
Zenitsu: Grey.
Shinobu, turning to Inosuke: Now tell him what color you think it is.
Inosuke: Dark white.