I have in the past completed few indoor murals. These were mainly within bedrooms for children, but one was within a room for elderly people who were unable to go outside unescorted.
The children rooms were created using mostly primary colours to brighten one wall and create a feature within the room, and I hope, to perhaps stimulate the imagination. The Disney themed one was for my cousneices and again in hindsight, probably flouted many copyright laws. The dolphins replaced it some years later and plain paint replaced them in time.
The room for the adults tried to be a little more realistic, although looking back it is rather over the top. It had a positive effect though, in bringing back memories for one of the residents. The chap used to be a woodsman and apparently he spoke more words in the room shortly after it was painted, than they’d heard him say since being at the residential home.