What round he would knock out his opponents in wasn’t the only thing boxing legend Muhammad Ali used to predict. He once said the U.S. government should put his picture on a stamp. “That’s the only way I’ll ever get licked,” he bragged. Well, the U.S. Postal Service went ahead and did it. The champ is on a stamp. “Those of you who knew Muhammad would have relished this moment,” Ali’s longtime wife Lonnie said during an announcement last week in Ali’s hometown of Louisville, Ky. “I know he would want this moment to be a teaching moment, too. This moment is an invitation to all of us, an invitation to pause and ask ourselves before every word we utter — what stamp am I making on this world?” Few Americans made more of an impact on the world than Muhammad Ali. He won a gold medal for his country during the 1960 Summer Olympics in Rome. Seven years later, he took a sacrificial stand against the Vietnam War, and was stripped of his boxing crown. “No, I will not go 10,000 miles from here to help murder and kill another poor people simply to continue the domination of white