Memorable cusp moments usually involve clashes of elements of both eras, such as someone brandishing a warning flag having to walk in front of the earliest motor vehicles.
I myself bore witness to a memorable cusp moment back in ... ahh, a long time ago. The venue was Western Springs stadium in Auckland, the performing artist none other than the new sensation from Whanganui, Johnny Devlin.
As everyone knows, Johnny was styled as the New Zealand Elvis. He had the hair, the hips and even a passing facial resemblance, and the teenie girls' ear-curdling shrieks let everyone know he was on the money.
This particular day was no exception, and Johnny wowed the whole crowd.
After the last of several encores, a whole bunch of hepped-up fans rushed the stage hoping to press the new sensation's flesh. The Kiwi Pelvis even deigned to descend from the stage's lofty heights and meet the throng on their own level.
I was one of the throng. Hey, what else do you do on a Saturday afternoon when you're a dumb kid and you have a chance to be in a crush comprised mainly of excitable teeny-boppers?
Being young and fit, I held my own in the thrusting throng and found myself in the inner circle now tightly hemming the Springs King.
Johnny was diligently signing autographs as fast as his guitar-pluckin' fingers could manage on whatever was thrust in his face — programmes, chip packets, even one or two real autograph books. Usually the fan supplied the writing implement as well.
Suddenly it was my turn. Being just a mercenary opportunist with ulterior motives, I had neither material to receive the star's scrawled moniker, nor instrument for him to scrawl it with.
But the brain was also young and nimble back then. It immediately instructed me to thrust out a bare forearm before he'd returned the pen he'd just used. To the rocker's credit, he immediately sized up my penless situation and duly scrawled his famous name on my proffered arm.
Or perhaps I should say, gouged his famous name.
You see, here was the cusp moment ...
The pen in question just happened to be of the type back then quaintly termed "fountain" pens — a lingering relic from a world the new-fangled "ball-points" hadn't quite yet conquered. As a more mature generation knows, the fountain pen featured a cleft nib which dispensed highly indelible ink — a very sharp and pointy cleft nib, in no way designed to navigate bare flesh.
Thus I entered the annals as one of rock 'n' roll's first martyrs to the cause. While Johnny engraved his name on the delicate skin of my arm, I smiled my appreciation back through clenched teeth — in rictus as they were from the nib's fiendish gouging. It felt like I was being tattooed by a red-hot nail.
The rocker from Whanganui was New Zealand's first superstar. He sold over a quarter of a million records in a few short years and now lives in Australia. While "Elvis" is an anagram of "evils", Johnny's surname similarly got the "devil". Between them, they rocked up some merry hell.
And with the magnifying glass I'm sure I can still see a very faint blue-inked "Johnny Devlin" deep-etched in my forearm.