episode 9 of season 3 was when an animator finally went
>wait a minute, the kumiko is showing on both sides of the shoji, that's not right.
up until this point it was always visible from both sides of the door
typically the kumiko(wood lattice) of a shoji door is exposed on only one side because you paste the paper onto it from the otherside, and then you have the wood lattice side facing inwards towards the room since that's where you'll be looking at it from most of the time.