About TETERI

A free, open-source block-stacking arcade game that runs in a browser tab, with no engine, no libraries and no asset files behind it.

TETERI is a block-stacking arcade game. Pieces fall into a well ten columns wide, complete rows vanish, and the run ends when the stack reaches the top. There is a marathon mode, a computer opponent at three difficulties, a split-screen mode for two people at one keyboard, and online duels over a five-character room code.

It is free, it needs no account, and there is nothing to install — though your browser will offer to add it to your home screen if you want it there.

What makes it unusual

Almost nothing in it was downloaded. There is no game engine, no framework and no third-party library. There are no sound files: every blip, slam and chime is generated by oscillators and filtered noise at the moment you hear it, and the soundtrack is a sequencer running a four-bar chord progression whose tempo and arrangement climb with your level. There are no sprite sheets either — the blocks are drawn to a canvas and cached as bitmaps at whatever size the layout worked out.

The whole thing is a handful of JavaScript modules, one stylesheet and a canvas. That is not asceticism for its own sake; it is why the game loads instantly, works offline, and runs on hardware that would struggle with a downloaded build of the same idea.

The rules it follows

TETERI implements the modern conventions the genre settled on: a seven-bag randomiser so droughts cannot happen, Super Rotation System rotation with wall kicks, a hold slot, a ghost piece, lock delay with move resets, and the guideline gravity curve. Scoring covers T-spins, back-to-back bonuses, combo chains and perfect clears. If you have played a modern stacker, your muscle memory transfers.

Independence

TETERI is an independent work. It is not affiliated with, endorsed by, or connected to The Tetris Company, Nintendo, or any other rights holder, and it does not use anyone else's assets, code or trademarks. The articles on this site discuss the genre's history, and where they name a company or product they do so to refer to that company or product, which is what trademarks are for.

Open source

The source is on GitHub under the MIT licence. The rules engine, the versus maths and the computer opponent run headless, so they are covered by a test suite you can run yourself with npm test.

If you want to know how a particular piece of it works, the How TETERI is built section goes through the rendering, the audio synthesis, the peer-to-peer netcode and the opponent's search.