Red Blob Games: algorithms you can poke at
Red Blob Games explains algorithms through game examples — A* pathfinding, hex grids, map generation from noise — with interactive diagrams you can drag and tweak.
What it is
Red Blob Games is the personal site of programmer Amit Patel. He makes interactive visual explanations of math and algorithms, using examples from computer games and his own projects. Instead of walls of formulas, you get diagrams where you can move a wall, a start point or a goal and watch the algorithm rework its answer in real time.
The best-known pages cover A* pathfinding alongside Dijkstra's algorithm and breadth-first search, a complete guide to hexagonal grids, map generation from noise, polygonal map generation with Voronoi diagrams, flow field pathfinding, 2D visibility, probability for RPG damage, line drawing, and curved roads built from Bézier curves and arcs.
Why we picked it
This is one of those sites programmers have been passing around for years. The hex grid guide has more or less become the standard reference for anyone building a game on hexagons. But the value goes beyond game dev: it's a masterclass in how to think about algorithms, and even with no coding background it's fun to drag the diagrams around and watch what happens.
It's very much alive, too. Patel keeps a blog on the site, and the latest post, from September 2026, is about programmatically choosing between "a" and "an" in English.
Where to start
- Read the introduction to A*; it's the best entry point.
- Open the hexagonal grids guide even if you have no game in mind.
- Play with map generation from noise: a few sliders and you've got islands and mountains.
- Skim the blog for shorter notes on current experiments.
Who it's for
Game developers and people who dream of making their first game. Students who need graphs and pathfinding to finally click. Computer science teachers. And anyone curious how a game character figures out a route around obstacles.
Quick answers
Do I need to know how to code? Not for the interactive diagrams. The implementation guides assume basic programming.
Is it free? Yes, everything is openly available on the site.
Who writes it? Amit Patel, who signs the site with his name and runs a blog alongside it.
