The rise of Andrew Robertson from youth player to member of the Scotland squad has been so rocket-propelled that one suspects it has been devised by NASA. How has a teenager who has played only 60-odd senior games of football become so conspicuous he cannot be ignored by Gordon Strachan?
How has a youngster who was helping to sell tickets for Bruce Springsteen and Olly Murs last summer played his way into the elite level of international football?
The fuse has been short but it has been marked by two explosive qualities: character and ability.
"He is a humble lad," says Mark Wilson, his team-mate at Dundee United. "You can sense he is grateful for where he is at such a young age. He is driven, too. Part of that might be because of a sense of rejection, as he was at Celtic as a kid, but I think most of it is just part of who he is."
Wilson, at 29, is a decade older than his fellow full-back but states without equivocation: "He is a talent. He has been our best player this season."
The fuse for Robertson the rocket, though, might have been lit with a trip to the seaside. The full-back, a product of St Ninian's High School in Giffnock, had been taken on by the Queen's Park academy and had impressed coaches. "Immediately, he stood out," says Dave McCallum, the Queen's Park academy coach.
"I came to the club after he had been in the programme for a year and was graduating to the under-16s. He was a stand-out because of his left foot but he was also athletic. You could see he was frustrated when he did not have an impact in a game and he was always keen to be involved, particularly going forward."
Robertson was no schoolboy giant but McCallum says: "There were no concerns about his size for us. Our philosophy is that we take the small players because when they physically mature you can see the natural ability has not left them."
His attitude was impressive. "He's confident but not overly so," says McCallum. "He is a strong-willed boy in that he takes direction and puts it into practice. The truth is simple; he is fine young man with a good family behind him."
It was a trip to Largs that provided the next impetus. Gardner Speirs, then manager of Queen's Park, took a group of players for a training programme on the coast. "Basically, I wanted to have a look at Andy to see if he could play some under-20 matches," says Speirs of the trip to the coast in the summer of 2012.
"Immediately, I saw he could play first-team football. His energy and drive were impressive but so was his temperament. He would take information on board and was desperate to learn. I planned to dip him in and out of the first team to get experience. But once he was in I could not leave him out."
He played 43 games in league and cup for Queen's and it was clear he was destined to move upwards, and quickly.
"You could see his concentration in his first training session," says Wilson, whose experiences include four championships at Celtic and a Scotland cap. "He realises the jump he has made and has taken that on board. He is a quiet guy in the dressing-room but he takes it all in."
Did the experienced Wilson ever feel the need to have a discreet word with the youngster? "Certainly not off the park in the sense of one-on-one," he says. "Frankly, he has been the best player for us this season. I have the odd shout to him on the park but that is just in terms of information rather than advice."
There were once concerns about Robertson's physique but Wilson brushes them aside. Robertson's height is given at 5ft 10ins and he is filling out.
"He is quick, technically good and can score goals," says Wilson of his team-mate, who has netted five times for United this season.
"In the past 10 to 15 years more emphasis has been placed on full-backs in terms of playing further up the park. You have to be a strong part of the attack, going deep into the opposition half to provide a cross or a shot."
This job description was made to fit Robertson. But the teenager has also improved defensively.
McCallum describes his protege as having "an excellent spring" to win headers in the box and Wilson agrees: "He can do it in the opposition box but he is strong in our area."
Robertson was watched in his debut for Dundee United by Strachan. "I thought he had something although he was a bit raw and had one or two things to learn," says the Scotland manager. "So we've kept an eye on him."
Famously, Robertson impressed the Scotland manager when the full-back trained with the squad before the Croatia game but McCallum reveals that the defender's Scotland experience goes back to before Strachan's debut on the sidelines with Scotland against Wales in March last year.
Robertson was part of a Queen's Park side that helped Strachan shape his side for the World Cup qualifier. He now has a more integral role in the Scotland set-up.
"He deserves to be where he is now," says Jackie McNamara, his club manager. "It is great credit to him and his family that he has gone from being told by Celtic that they didn't want him, on to amateur football with Queen's Park, signed for us and now he is in the Scotland squad. That speaks volume for the progress he has continued to make." He adds: "I would challenge anyone who has watched us play this season to be surprised by this, though."
Yet even from a short distance the launch of Robertson has been spectacular. "I have never seen the likes of it in my years in the game," says Andy McGlennan, a director at Queen's Park who also describes himself as a '68-year-old dinosaur'."
In his day job as debenture services manager at Hampden Park, McGlennan took on youngsters from Queen's Park over the summer to help him handle ticket sales and other matters for the likes of Springsteen, Murs and Bon Jovi and Robbie Williams.
"A lot of guys have had an input in the lad's rise," he says, playing down any link to Robertson the footballer.
But he adds: "It is strange to think he was sitting in my office in the summer helping me out and months later he is in the Scotland squad. He is a fine lad, a listener and a learner."
The take-off from Hampden has been followed by a spectacular rise at Tannadice.
The spectacular trajectory is now being watched by the likes of Roberto Martinez at Everton and Gary Monk at Swansea City.
The fuse has been lit and now Robertson is heading to Poland. The full impact, one suspects, has still to be felt.