"Stay inside the lines" means to follow rules. It refers to coloring a picture neatly and accurately. A merry go round is also called a carousel. You often seen it at a fair or an amusement park. http://www.merriam-webster.com/dictionary/merry-go-round Definition of MERRY-GO-ROUND 1: an amusement park ride with seats often in the form of animals (as horses) revolving about a fixed center