“I'd been building a lot for Emma which is this archetype that I had in my head who's my little sister. She was entering college as a first year civil engineering major and we were thinking a lot about how can we summarize things help people learn.”

Build for one real person — Zack's sister Emma, civil engineering major

Zack grounded every product decision in a single concrete person: his sister Emma starting civil engineering. Building for one real human instead of a fuzzy demographic sharpens every trade-off, especially when you can text her after a release and ask what she thinks.