What is the fine-grained topic of the following text: It was here, in the more than 60,000 square metres of precious houndstooth, tweeds and other cloths that Hublot and Lapo Elkann found a collection of tartans—squared coloured wool weaves from the seventies—that they brought back to life by including them in the Classic Fusion as a chronograph. Only return the topic.
Hublot and Lapo Elkann's use of vintage tartans in the Classic Fusion chronograph design