Took out some pistons today with little run time on them and a good example of ring contact. First picture you can see the dot on the second ring showing up. In this picture the top ring is a D faced (or some call it a barrel face) Moly ring. The wear is in the center and doesn't go all the way to the edges. Second ring is a reverse taper. You cans see a light wear (shiny) mark on the bottom of the ring. That is the only part that touches the cylinder wall.