As Craig and Jamie Overton sat on the outfield at Headingley, addressing the media two days out from potentially being the first twins to play in the same Test match for England, it was hard not to look upon the pair as a control experiment.
Here were identical twins, born in Devon, raised in a cricket mad household, getting more or less the same coaching and opportunities through the age-groups at North Devon and the Somerset academy. Craig got a call-up for West of England first before Jamie pipped him into the England Under-19s, only for Craig to retake the lead into the full side with eight Test and four ODI caps.
There have been divergences of choice, both professionally (Jamie moved to Surrey in 2020) and aesthetically (Jamie has also grown a beard). But both men sport broad six-foot-five frames, the most intriguing differences for the purposes of this week (and their careers) is that Craig has become a bustling allrounder while Jamie an express quick.
Evidently, Jamie's greater pace was identified from a young age, with Craig having to get used to bowling uphill into the wind to give his brother every chance to tick the speedometer into the red zone. And with that has come the reliability of Craig and the difference-making nature of Jamie, which has been honed enough this season to earn his call-up, after 21 Division One wickets at an average of 21.
"I'm not the one who can bowl at 90 miles per hour," cedes Craig, "So I've always been that person who bowls steadily and I haven't had that X-factor that you sometimes need as a 90mph bowler.
"I know I can hit line and length pretty well and try to use my skills a bit more than brute force and brute pace. As I've got older, I've understood that a bit more. I've not tried to bowl 90mph because that's not me, so I've let him do that and I've tried to do the basics and not go for many runs, and let him hit people in the head."
A pointed last remark, no doubt, after Jamie did just that to fell his brother in a County Championship match between Somerset and Surrey last week. Craig was able to continue - his team-mate Josh Davey, also hit later on by Jamie, could not - but had to be removed from the match after failing a concussion test the next day.
Upon Craig's return to the crease, Jamie greeted him with another bouncer. "I don't want to take too much credit for that actually," clarified Jamie. "I asked Rory Burns [his Surrey captain] what he wanted to do. I said 'do you want to go at them again or try to nick them off?' And he was like 'go at them again and then try and nick them off'. So when he came back in, I managed to bowl a quicker ball than the one before and he just managed to get underneath it."
"I would say he did me for lack of pace - I was through the pull shot too early," joked Craig. "No, it was quick. The one I came back in to afterwards was probably the quickest ball he bowled all spell, so that was a nice welcome back." He went on to confirm Jamie was the quickest he had faced so far this season, an opinion shared by many a batter on the domestic circuit.
That evening of their battle, their father, Mark, tweeted his pride at his "two littluns today who both pushed their bodies to the limit and showed guts and determination. It wasnt easy watching but god Im proud". Hard viewing, maybe, but no less than what he would have expected them to be against each other, according to Craig.
"I think they [their parents] would have told us off if we weren't giving our all, so it's always 100 percent, whatever we do. If we didn't, dad would definitely tell us off." Both parents will be up on Thursday to witness an occasion as emotional for them as it will be historic for the English game. Sisters Jane and Jill Powell are the only previous England twins to play Test cricket, but Jane's six Test appearances, between 1984 and 1987, came long after Jill's solitary appearance back in 1979.
To those who know them well, or have watched their path for however long or short, the most notable thing they share beyond the looks and 28 years (Craig is three minutes older) is a relentless feistiness. So much so that Somerset coach Jason Kerr used to split them up at training to avoid confrontations, ensuring they either bowl together or bat at the same time. Something after last week, the first time they had faced each other in a proper game, Craig reflects on as "a wise decision".
That fire in a competitive environment is only exacerbated by both trying to make their way side by side. Craig recalls the lead-up to his first-class debut, against Lancashire in April 2012, when both were in contention for one spot. "We both said to each other before we found out, 'whatever happens, we'll be supportive'." They have maintained that pact ever since, through various Lions tours and one-day squads. Just as Jamie only had to wait three weeks to get his own maiden first-class appearance against Surrey, his opportunities were never going to be too far away.
But Jamie's call-up to the Test squad was certainly not a foregone conclusion, least of all to the man himself. Issues with his run-up and radar blighted him all of last summer, in which he took just six wickets across eight matches at a dreadful average of 75.66. Those issues, while in the process of being resolved by the start of this season, meant he began it out of Surrey's first XI before finally coming good on a shorter run-up honed with the club's bowling coach Azhar Mahmood.
"I was losing so much energy actually running in, as I was slowing down as I got towards the crease," he said. "Whereas now I'm still accelerating towards the crease and someone said to me I look a lot more controlled through the crease."
Ultimately, that experience has reinforced the contract between the two. And a decade on from their first-class debuts, their presence in the Test squad, individually, provides England with options to rotate ahead of back-to-back Tests (they play India in Birmingham three days after this match). But as a pair, they could help retain the existing balance of the XI, even if captain Ben Stokes is ruled out through illness.
"We know how to get each other going, that is for certain," answered Craig when asked if they have always dovetailed well in their careers - a response which tells you all you need to know about the aggressive brand of cricket they both enjoy. "When we were 17 or 18 back home, and then at Somerset, it was always pretty special and we bowled pretty well together. We should bowl well together because we have done it since we were six years old. It will be good fun, and hopefully we will get a chance together."
Absurdly, whether standing at mid-on or on the sidelines wearing a bib, this will be the first time Jamie has watched Craig play for England. He went to The Oval last summer for England's Test against India but missed his brother's batting due to training in the morning, then left early and missed him bowling.
For everyone else, watching Jamie turn out in an England shirt will be long overdue. And should the Overton twins do so together, it will merely be a realisation of what many within Devon, Somerset and English cricket have talked of for a long, long time.