We planned this craft for both of our classes at church.  As crazy as it sounds, I cut out all the pieces ahead of time.  At first I was just going to do it for the younger kids, but once I got started cutting, I realized how much there was and how difficult the waves were.  Due to time constraints and thinking the kids would get frustrated, I decided to cut out all the pieces for all ages.  It was a lot of work!  If you do the same, give yourself plenty of lead time.  I also made a sample so the kids would understand where the pieces went and how they fit together.  The pattern comes from dltk-bible.com.