There’s an indoor lamp without a cover hanging from the ceiling. Only two out of four possible bulbs are installed. There are burned-in soot marks leading from the wall to the ceiling.
NemZ: I thought that was black mold. This just rouses the further question of what the hell was burning to leave that much soot residue... perhaps a grease fire? Was it something that Rei did or is it leftover from previous tenants?
Kendrix: As for the source of the soot, it kinda looks like what accumulates over a heating after many years, with the lack of light making it look worse than it is... Not sure if there's even a heating beneath it, tough. Might've been any sort of domestic accident.
UrsusArctos: Fluorescent lighting is more common in Asia than North America. A burning electrical appliance at the corner could explain the soot stains. The implication could be that Rei is so bad at living she doesn't care if one of her few possessions is on fire.