Alysa Liu won Olympic gold in women’s figure skating by skating loose, smiling and doing it her own way. On Thursday night, the 20-year-old from California delivered a free skate that looked like a fun practice session, rather than a pressure test. She waved to friends and family and grinned through her program. She finished with the top score and beat Kaori Sakamoto and Ami Nakai. The win gave the U.S. its first women’s Olympic gold since 2002. It was the culmination for Liu of a two-year comeback after an abrupt retirement following the Beijing Games, when she was too burned out to continue.