When Isaac was born four minutes ahead of his twin Henry he screamed. But as soon as his brother emerged safe and sound in the world, he quietened immediately.
The boys have lived largely parallel lives to the age of 12, but now it is time for them to separate again.
At high school.
On Monday morning, Isaac and Henry will head in opposite directions for the start of the academic year. Isaac has enrolled at Lyneham High, while Henry has chosen Campbell High. The Ainslie Primary graduates were drawn to their respective high schools during open days.
Henry says of Campbell: "I liked teachers who spoke to us and interacted with us. I just liked the feel of the rooms and corridors, the displays on the walls of projects and art that was really fantastic. I'd love to be able to do some of that."
Isaac is following family tradition - his elder sister Sapphira is in year 9 at Lyneham and his father also went there. He prefers Lyneham's arts, sporting and band programs.
Of the two he is the more artistic.
When they started kindergarten, the twins chose to sit next to each other, and they were in the same class in years 1 and 6.
But by the end of last year it became apparent the boys were being drawn in different directions and they had to make a choice both admit was difficult.
They did not try and persuade each other to stay together at the same high school even though they knew it will feel strange not being together.
"When Isaac was thinking about going to Lyneham I didn't try and talk him out of it. I just want him to be happy and to do whatever he wants," Henry says.
"I think it is going to feel weird not being together. I'm not sure how it will go," Isaac says.
Their parents supported the boys having the freedom to choose the high schools that suited them and felt fortunate that Canberra had such good public schools. Even if this meant a double drop-off when they could not ride their bikes.
While the boys joke that it will no longer be possible to copy each other's homework, or, more seriously, to be there for each other throughout the day, their overriding emotion is one of excitement.
"I'm totally looking forward to high school," Isaac says.
"Yes, but we will be little fish in a big pond instead of the other way around," Henry says.
And perhaps the biggest change will be their ability to forge independent relationships with their peers where there is no confusion over their identity.
"It does get a little bit annoying being asked whether I am Isaac all the time," Henry says.