It’s long been commonplace for networks to pimp their sponsors by overlaying virtual — or digital — logos over playing fields and basketball courts. But faking an entire fireworks display? If you ooh’d and aah’d while watching the opening ceremonies last Friday, what impressed you was the digital handiwork of Gao Xiaolong, head of the visual effects team for the ceremony. The 55-second sequence took almost a year to create as motion graphics experts consulted with meteorologists about how to recreate smog in just the right light.