The circles represent the following: - red is one week - orange is a day - green is an hour - blue is a minute - purple is a second -grey is your life(why you need to enter what year you were born(the default is 1992)) Scratch doesn't like fast swapping of costumes so occasionally the purple circle pauses for up to 5 seconds. Settings changes between light mode(white background) dark mode(black background) and the other two alternate backgrounds. Day / Night is light mode between 6am and 6 pm while AM / PM is light mode during AM.
