The mathematical purpose of this lesson was quite clear. Students learned that the area has the same measure, when the sides of 2 pentaminoes touch. This puts to mind one of my classrooms that had tables instead of desks. Whenever tables were grouped so that their sides touched, the area stayed the same but the perimeter changed. Of course this changed the amount of seating available as well. This would have actually been a great lesson for this concept. Less perimeter equals less seating.