Water Bottle IDs

So, what do you do when you have four of the same water bottles that everyone in the house likes to use? Most people would either a) Not own four of the exact same water bottles to start with, or b) Just break out the closest Sharpie and write names on the bottles.

Me? I break out my small stash of washi tape and make everyone choose a color. After I attached the tape to the bottle rings, I had to keep going and cut them into a pretty flag. Ta-da! Everyone has their own color to ID their bottle, and I don't have to worry about drinking backwash sharing germs with the boys.

Do you have any tips for keeping similar cups and bottles with the correct owners?