Look, Mom! There are lots of mirrors! My son greeted me as I walked into the bathroom to help him brush his teeth. He was absolutely fascinated by the reflections bounced back and forth between the medicine cabinet mirror and the main bathroom mirror.
Where does the light start? (From the bulb on the side of the mirror.) Where does it bounce to next? (Your face.) And then? (To the mirror.) And then? (The other mirror.) And then? (The other mirror.) And then? (The other mirror.)
Does all the light keep bouncing back and forth? (No, the picture gets darker.) Some of the light is getting dispersed in other directions, and not continuing to bounce. That is entropy. All known processes loose a little energy as they go.
Of course, he does not get all that right now, but I do smile when I walk into the bathroom and find him using his finger to trace the path of the light as it bounces back and forth.