In Simon Reynolds’s coruscating history of post-punk, Rip It Up and Start Again, he argues that revolutionary moments in pop culture (such as punk) have their broadest impact after the radical moment has actually passed (hence post-punk). I was musing on this the other day in relation to beauty trends. A prime example is the return of curly hair. Avant-garde girls were working the unreconstructed 1980s perm as far back as the late 1990s. Then it transmogrified on the streets from the soft militancy of those old-school perms into what I call the indie-girl shag or bedhead (side-swept fringe and ruptured, razored waves). Until finally, last summer, the blonde one on Big Brother had this wavy, shaggy morass, and the celebrity hairstylist Eugene Souleiman declared that straight hair was in the vanguard of art coiffure. Then you realised that the curl would shortly die. With clothes, trends appear to undergo a tectonic shift every six months. Beauty, by contrast, advances with a Mogadon trudge: for the past 18 months, for example, there has been an irritating trend towards natural make-up. I suppose my point is that, as with post-punk, the most interesting moment may not be at the beginning. We need to track a trend’s modulations from avant-garde to mainstream to a gentle fade-out at the end.