smile again. and for the first time in two weeks, she is playing again. a russian gymnast is being investigated for displaying a symbol which has come to represent support for russia's invasion of ukraine. ivan kuliak taped a letter �*z�* to his chest on the podium at an event in doha, after winning bronze. he was standing next to the gold medal winner — who was ukrainian. the international gymnastics federation called it "shocking behaviour" and opened disciplinary proceedings against the russian athlete. the letter z has become become symbolic of russia's invasion of ukraine. you can see it painted on the side of these russian military vehicles in crimea. it's also being used by pro—russian protesters showing their support for the invasion. this is the serbian capital belgrade. professor sergey radchenko is a historian and russia specialist at thejohns hopkins school of advanced international studies. he joins us from cardiff.