Rebuilding Yumbee: Remastering My Dad's Dice Game from 2003

Growing up, Jamb was a game everyone in my family played competitively. And if you’ve ever met someone from the Balkans, they’ve probably tried to teach you. Jamb is a dice game similar to Yahtzee but with way more strategy. You have multiple columns with different constraints: one must be filled top-down, one bottom-up, one requires you to announce your choice before rolling, etc. The game rewards long-term planning in a way Yahtzee doesn’t.

Back in 2003, my dad coded his own version in Visual Basic 6 and called it Yumbee. It ran on Windows XP and our family played it for years. Watching him build that game is one of the main reasons I got deeper into coding throughout high school, encouraging my own experimentation.

Finding the Original CD

While visiting my parents for Christmas holidays, we found the original CD with Yumbee.exe. My dad kept it all these years and, to our surprise, it loaded up just fine and still ran on Windows 11! Playing it again after more than 20 years was a trip. The game logic was solid, and all the little scoring nuances my dad had carefully implemented were still correct. But the UI was very much of its time.

We started talking about what it would look like rebuilt for today, which quickly went from a joke to a plan.

The Build

The tech stack is Next.js and Tailwind CSS, deployed on Vercel. I used AI to speedrun the development. The core game logic, responsive UI, multiplayer, and AI opponent came together in between holiday gatherings over about two weeks. Without the help of AI, this would have been a multi-month coding slog, especially the matched-dice multiplayer and the amount of layout work necessary for the many variants of the game.

My dad served as Product Manager. He had very strong opinions about the rules and scoring, which turned out to be more nuanced than I remembered. There are subtle interactions between the column constraints and scoring that you only really know if you’ve played Jamb for decades. Every time I thought I had the logic right, he’d find an edge case.

My mom was Lead QA. She’s the strongest player in the household and played dozens of games, catching bugs I never would have found. There were several gnarly issues with the announcement column, where declaring your intent and then rolling spews edge cases. I coupled her testing with Playwright and a simulator that played 10,000 games using property-based testing and fuzz testing. Random walk simulations played entire games making random moves to find crashes and stuck states. Between my mom’s intuition and the simulator’s brute force, I’m fairly confident the game engine is rock solid, even for custom rule combinations.

The final version supports several game variants (classic, modernized, and pro rulesets plus fully custom rules), a tutorial for people who’ve never played Jamb, and AI opponents. I also added a seedable PRNG so you can challenge friends to the exact same dice rolls and compete on pure strategy without excuses around bad luck. The whole thing works offline as a PWA with state persisted locally, so you can play on a plane or subway without losing your game. There’s even haptic feedback on mobile when you roll.

The tutorial was important for me to get right, given Jamb is not well-known outside the Balkans. I really wanted anyone to be able to pick up this fun and surprisingly deep game. I also used AI to translate the whole app into multiple languages, which worked surprisingly well and added some nice polish.

Bringing It Full Circle

AI is ushering in the golden age of side projects. My dad got to see his 23-year-old creation come back to life. My mom got a new version to dominate. And I got to share a little of my work with my parents in a deeply personal way.

You can try it yourself at yumbee.app. Let me know what you think!