DD is 21 months. Whenever she plays with her of toys of plays the games she plays, she always does everything in the same order. For example her toy animals she always lines them up in the same order in the same place, then plays with them. She has lots of other little rituals that she does throughout the day which are similar to this. If she paints/colours she always uses the colours in the same order. And also likes to correspond her paint brush colour (handle) to the paint she's using. I've not noticed any other children her age doing this sort of thing.
I'm not worried about it exactly, it's just a funny quirk she has, but wondering if other children do this sort of thing to?