I hate kids. Can’t stand them. I want them to stay away. I don’t like them, I don’t like to play with them, I don’t think they’re fun, I don’t think they’re funny, I don’t think they’re cute, just keep them away from me.

Then I had my own. Turns out I hate all kids except mine. Convenient, but it left me with a problem. I still hated all the stuff you’re supposed to do with them. I don’t play pretend, I don’t do dolls, and if I have to sit through one more round of hide and seek, I might just let them win by disappearing myself. So, I had two options. Fake my way through games I couldn’t stand and connect with my kids anyway, or find something else.

What I noticed was that my kids asked a lot of questions. And since I’ve never been good at talking down to anyone, I just answered like I would an adult. They didn’t get it, so I’d break it down. Simpler, then simpler again, until it clicked. Turned out I was good at that part. My kids liked figuring things out, and I liked watching them get there. That was our thing.

I started writing session ideas in my phone’s notes app between one thing and the next. How do you get a nine-year-old to feel why time dilates? I tried pen and paper first, then wanted more room, tried to buy a whiteboard, got vetoed by my wife, and ended up with chalk markers you can draw on glass with instead. Marker Sessions was born on a kitchen window.

We did them on everything. Physics, history, money, why the ocean is salty, why revolutions happen. Other dads started asking how I had the patience. I never did, really. My answer was always the same. I don’t play pretend, I don’t do the pool, I don’t do dolls. But I know things, and I can explain them. That’s the whole trick.

I’m not a company. There’s no team behind this, no funding, just one dad building something between putting kids to bed and starting the next session’s notes. If something’s rough around the edges or a feature is missing, that’s why. It’s being built by one person who’s also, at that exact moment, probably being asked to play hide and seek.

Do I think my nine-year-old actually understands the economics behind a revolution, or my seven-year-old understands the mathematics of General Relativity? Of course not. Kids can’t hold that much. But if they walk away with one new piece of the world, that’s one more piece than they had, and a memory that’s just as much mine as theirs.

This started as notes on my phone because I needed it, not because I planned to hand it to anyone else. But once I saw what it did for me and my kids, I couldn’t just keep it to myself. There are a lot of parents out there who love their kids and still dread the floor and dolls version of parenting, who feel guilty for not being the parent who plays. I built this so they don’t have to fake it either. You don’t need to be good at pretend to be good at this. You just need to be willing to sit down and explain the world to someone who wants to hear it.

There’s a line from Interstellar that’s stuck with me since I started this. Cooper is leaving his daughter for a mission that will take years, maybe the rest of her childhood, and he says his wife once told him something. “Now we’re just here to be memories for our kids.” He says once you’re a parent, you become the ghost of your children’s future.

That’s what this is. One dad, figuring it out as he goes, trying to make sure the memory is a good one.