You reached out and touched the screen and a small sharp crack of static electricity bit your fingertip, and you pulled your hand back, and then — because you were seven years old and the thing was glowing green — you reached out and touched it again.

The CUB monitor sat on a desk at the back of the classroom at Wheatcroft Primary. Green phosphor. The kind of green that exists nowhere in nature, a green that said: I am made of electrons and I have opinions about your hand. It was paired with a BBC Model B, and together they constituted the school’s computer, singular, which tells you something about the era and something about school budgets and something about how much has changed in forty years. One computer. One classroom. A rota.

The static shock was real. Not a tickle — a proper snap, the kind that made you flinch and then look around to see if anyone had noticed. I don’t know if it was a grounding issue or simply what happens when a cathode-ray tube runs for six hours in a room full of nylon jumpers, but it was consistent. You approached the CUB monitor with a specific respect that had nothing to do with its educational value.

What ran on it, mostly, was Granny’s Garden. You navigated a text-and-graphics adventure to find ingredients for potions for an elderly witch. It sounds, described baldly, like homework dressed in a hat. But it wasn’t. The puzzles were actual puzzles. The map was genuinely explorable. You could get properly stuck, in the way that games now spend a great deal of money simulating but rarely quite achieve — the stuckness of a system that does not know or care whether you are frustrated, a system that will simply wait while you work it out. There was also Castle Quest, which was harder and darker and felt like it had been designed by someone who didn’t much like children. I respected it for that.

But the one that stayed with me was Daredevil Dennis. A side-scroller. Not sophisticated by any measure that would apply today — a few dozen pixels of a man on a bicycle, obstacles, a score. What it had was speed. On that green screen, in that back corner of the classroom, with the monitor crackling faintly if you let your sleeve get too close, Daredevil Dennis moved, and you moved with him, and for the duration of your turn on the rota you were somewhere entirely else.

I have tried, over the years, to explain to people who weren’t there what that felt like — the specific quality of that experience, that particular combination of machine and moment. The word I keep coming back to is beautiful. Which I know sounds like the kind of thing someone says about a sunset or a proof, not about a green phosphor display in a primary school classroom. But I mean it in the structural sense: it was beautiful the way a very simple, very correct thing is beautiful. Here is a machine. Here is a problem. Here are the rules. Go.

What the BBC Model B offered, that almost nothing else in my life at that age offered, was time to just be me, play, explore. No social register to read. No hierarchy to navigate. No performance required. The machine was indifferent to whether you were popular or funny or quick on your feet in conversation. It cared only whether your input was correct. That was, to a particular kind of child, an extraordinary relief.

My father was a tradesman who could turn his hand to anything — engines, electrics, anything physical — and I had absorbed from him something about the pleasure of understanding how a system works. Not just using it. Understanding it. The BBC Model B, if you were patient with it, would show you its workings. You could drop into BASIC from almost any program. You could type LIST and see the code. You could change a number and see what changed. This was not an accident; the machine had been built with the explicit philosophy that you should be able to get under the bonnet. It was a computer that treated you as someone capable of understanding it, which was not a universal assumption in 1984 and is not, honestly, a universal assumption now.

That approach — poke at it, see what breaks, modify a thing and trace the consequence — became how I read systems. Not by reading the documentation first. By running it. By disassembling it. By the empirical method: hypothesis, intervention, observation. No formal computer science. Just the implicit lesson that a system will teach you if you ask it correctly. That lesson lived in my hands before it lived in my head.

I didn’t know any of that at seven. I just knew that when my turn on the rota came I walked to the back of the classroom and sat down in front of that green screen and something shifted. The noise of the room fell away. The monitor hummed very faintly. And for twenty minutes — or however long they gave us, it never felt like enough — I was entirely, uncomplicatedly present.

I touch screens all day now. None of them shock me any more.

I’m not sure that’s entirely a good thing.