I believe it is a boat. If you look closely, the rear lines actually seem to be slightly behind the main body (wakes from a previous wave). In boating, if the boat is cresting upon many waves, then you can actually see the wake where the boat returns to the crest of the next wave, accounting for the lines from the middle of the boat. The line directly behind is where the water is returning from being displaced by the boat's previous travels.

I agree, teachers make the biggest difference in most children's lives. My wife is a new high school math teacher with emphasis in special needs education. I have dealt much with teaching (tutoring and mentoring along with having done internships through schooling) and have seen both sides. As with anywhere, there are teachers that simply lecture from a book, assign work from that book, write exams from that book, and take nothing home. Then there are those who make special assignments and activities (hidden assignments) that assist students with learning in a way that they can better relate. These teachers, those who spend much of their time outside of the classroom preparing, meeting with students, etc. don't make enough. They are the true heroes and backbone of our country. Without them, we wouldn't be where we are today because we would be a largely uneducated or undereducated society. THANK YOU TEACHERS!!!