The younger of the two has made a special art of slipping under the radar.

After six years we have, at last, committed her name to memory but there are still new things to learn about Clementine every day, such as the fact she can now make her own breakfast ... and read.

I’ve written about this in the past – about how with the first one you tend to hang on their every developmental milestone, write highlights down in special books and rally the rellies for important announcements such as: “The boy just identified his first dipthong blend” or “we think he may be gifted at hopping.”

It’s fun at the time but it gets a bit exhausting and even slightly silly.

By the time the second one came around, Tracy and I had settled on a more relaxed framework for measuring developmental achievements. We essentially threw the ruler away.

However, the kid would regularly dig it out and whack us with it just to make sure we were paying attention.

I experienced one of those moments just this week.

Working from home these days, school holiday time usually means I have two small business associates sharing my office space.

I have put them to work on the Be Very Quiet When Dad’s on the Phone brief, and for the most part, they are making a valuable contribution.

If they meet their Key Performance Indicators (KPIs) such as not entering a raging argument about whether it would be better to have a swimming pool filled with custard or one filled with jelly while I am taking a conference call, I incentivise them with cold Milo and cartoons in the afternoon.

At this point in time, as I am typing these very words, the house is so silent I can hear the ticking of the wall clock and the warble of a magpie perched on a limb of the avocado tree outside.

Hank is in his bedroom reading Dragonfox and Clem is in the kitchen drawing a picture. I must make haste while I can before the inevitable happens and I am interrupted because they say they are hungry, which usually happens every 15 minutes or so.

Once fed, they will hear the familiar mid-morning office mandate. “It’s a beautiful day, now go and play outside.”

And it was during this post-mid-morning-second-snack period on Monday when I was reminded how the younger one had grown some more while nobody was looking, as she does.

This time it occurred in the areas of adventure, independence and dangerously replicating what she had witnessed on television.

I was quietly tapping away on the keyboard. I could see Hank through my office window, hunting the family dog Vossy with the Mexican bola he had made with rope from the shed and, thankfully, tennis balls instead of rocks.

Then Clem showed up on the radar. Her unmistakable helium-fuelled voice rose from somewhere out the front of the house, comforting me that she was close by until I listened more closely to her words.

“Challengers are you ready? Gladiators are you ready?” she called, before launching into the ominous countdown. “Three, two, one!”

By the time I arrived at the scene it was too late to intervene.

She was sitting in her brother’s red wagon, with the handle rotated around to act as a steering device. With bicycle helmet and excited smile on, she was thundering down the driveway towards the street.

Her favourite stuffed toys or her “guys” as she calls them, had been arranged as spectators down the run to cheer her on.

Well, perhaps I’m exaggerating a little when I say that the wagon was thundering.

It was probably more of a trundle. And the driveway isn’t sufficiently steep to result in an overly concerning amount of forward projection out onto the bitumen – barely enough to have propelled her over the lip of the gutter in fact.

Still it was sufficient to make a father’s heart flutter in fear of what other gladiatorial conquests she might have been getting away with under the supervision of bears, fairies, unicorns and others.

And swell with a peculiar sense of pride at the same time.