Recent studies presented by researchers who attended the Twins Days Festival in Twinsburg, Ohio, visually showed the effects of smoking over a period of time.  The study interviewed 79 sets of identical twins and photographs were captured to show the effects smoking had on the twin who smoked compared to the one that didn't.  One of the interesting findings was also the level of visual difference between twins who have as little as a five-year difference in the amount of time they've smoked.