How to play Rombobox

A logic and reflex game for your browser: light up the four colors and reach the goal by the shortest path, without losing your rhythm.

The board

You play on a 4×4 board. Every game the 16 squares are placed at random, including the start and the goal, so no two games are ever the same. You move a yellow rhombus from square to square, horizontally or vertically.

• Start. Your rhombus appears here.
• Goal. Reach it with all four colors lit to win.
• Color pairs. There are four colors (green, red, yellow and blue), each on two squares.
• XX squares. One per color. They turn their color off.
• Neutral. Just for passing through.

Light up the colors

The four colors start off (they look dark). When you step on a colored square, you jump to its partner and that color lights up. The jump is instant and doesn't count as a step.

You step on green, jump to its partner and green lights up: 1 step.

Hard to tell the colors apart? In ⚙ Preferences you can turn on shapes on the squares: each color gets its own symbol (● green, ▲ red, ■ yellow, ◆ blue), on its X squares too.

Watch out for the X

Each color has an X square of the same color. Step on it and that color turns off again, even if you already had all four lit, and you'll have to visit its pair again.

Stepping on the green X turns green off again.

Reach the goal

You win when you step on the black square with all four colors lit. If you step on it earlier, nothing happens: you can keep playing and use it like any other square.

Steps: the optimum and the maximum

Before each game, the game computes the optimum: the fewest steps that solve that board. At the top you see your steps and the maximum allowed, which is the optimum + 2.

If you finish without nailing the optimum, win or lose, the final message draws one of the optimal paths on the board, step by step, so you can learn the shortcut. Tap the board and a comparison opens: your path and the optimal one, each on its own board with its own step counter, moving at the same time.

Momentum

With your first step the board lights up: that's your Momentum. If you take more than 1.5 seconds between two steps, it goes out, and to win you must reach the goal with your Momentum still on. That's why it pays to have your route clear before you start moving.

Thinking time

Before your first step you get some time to study the board (the First step time counter). In your first game it's unlimited; after that it depends on how you played the previous one. If it runs out before you move, you lose. You'll never have less than 3 seconds.

Your first step chooses the game mode

Without saying it, the moment of your first step decides how you play that game. Two lights below the board help you: the ⚡ is on during the first 3 seconds, and the red light turns on when 3 seconds or less are left.

Time and bonus

If you win, your thinking time for the next game is the time you used + the bonus. The bonus is the time you had left: doubled if you nail the optimum, as is with optimum + 1, and nothing with optimum + 2. It applies in all three modes. If you start in the last 3 s, those seconds aren't deducted.

The blackout

As your streak grows, the game gets tougher. From a streak of 5, one of the two neutral squares is a blackout; from a streak of 10, both are. From the outside they look like normal neutral squares.

If you step on a blackout, the whole board turns black, like the goal, until the end of the game: you'll only see your rhombus. The rules don't change, so you'll have to remember where each color, each X and the goal are. When the game ends, the board becomes visible again.

So close! and losing

If you reach the goal missing only one of the two conditions (no Momentum, or more steps than the maximum), the game is a So close!: your streak doesn't go up, but you don't lose it either. Your thinking time and accumulated Momentum stay the same.

You lose if you miss both at once, if your thinking time runs out or if you abandon a game in progress. Your streak goes back to 0 and everything starts over, with unlimited time.

🏆 As long as you keep winning, you won't see full-screen ads. They can only appear when you retry after losing.

Playing without seeing

Rombobox has a mode you can play by ear only, designed for blind and low-vision players, and for anyone who wants a different challenge. Choose it on the home screen with 👂 Play without seeing (or the S key). The rules and the streak are the same; what changes is how you receive the board, and the timings.

How you hear the game

The first time, you choose between the browser voice (with the voice and speed you prefer) or your screen reader (NVDA, JAWS, VoiceOver, TalkBack), which you'll hear with its usual voice and speed. You can change it in Preferences.

The board in words

Each position is said as x y: column 1 to 4 from the left and row 1 to 4 from the top. The squares are named like this:

• 1, 2, 3 and 4: pairs turned off (1 green, 2 red, 3 yellow, 4 blue); 5, 6, 7 and 8: the same ones, lit.
• 1 X to 4 X: the X of each color.
• N: neutral (a blackout also sounds “N”). start and goal.

First you simulate, then you play

While you think, the arrows simulate: the game applies the rules (jumps, X squares, colors) and tells you where you land after each move. N reads the whole map, left to right and top to bottom, and M tells you where the goal is, which colors are missing and how many steps you've taken.

Press Space to start: the simulation ends, the rhombus goes back to the start and the real game begins. That Space counts as your first step for timing, Lightning mode and the bonus.

During the game, each step sounds where it is (left or right by column, higher at the top and lower at the bottom) and the edge sounds like a dull thud. Space tells you your position and your neighbors (up, right, down and left, or “edge”); if you hold it (or press D), you also hear each neighbor's position. N and M still work.

The sounds of the squares

Each step sounds with the instrument of the square you step on: green, flute; red, clarinet; yellow, marimba; blue, little bell. Off is one note and lit, two. The X sounds with its color's instrument and a buzz; the neutral square is a click, the start a rising sound and the goal a low bell.

The S key plays the sound map: all 16 squares in a row, left to right and top to bottom, each in its place and with its instrument. It's faster than the spoken map (N), but you need to know the sounds. To learn them, on the home screen there's 🎧 Train your ear (E key), with three exercises: Where is it?, Which square? and Explore a practice board.

Timings

Momentum is 4.5 s between steps (it starts with your first real move), the Lightning mode window is 9 s and its extra Momentum is also times 3. Everything else —thinking time, bonus, the last 3 s, So close! and losing— works just like in the normal mode.

The blackout without seeing

From a streak of 5, if you step on a blackout you'll hear “Blackout” and, until the end of the game, Space, D, N, S and M stop working. All you have left is your memory and the sound of your steps.

Voice control

You can turn it on in Preferences (it only works in this mode). Say “up”, “down”, “right” or “left”, and also “start”, “position”, “around”, “map” and “goal”. It works in Chrome, Edge and Safari; it's best with headphones, so the microphone doesn't hear the game's voice.

If you already use your system's voice control (Voice Access on Windows, Voice Control on Mac and iPhone, Voice Access on Android, Dragon…), it works too without turning anything on: every action has a key. Say, for example, “press right arrow”, “press space”, “press D”, “press N” or “press M” (the exact phrase depends on the program).

On a phone

Above the board there are three buttons: Start or Position (hold it for details), Map and Goal. The arrows are the touch panels on the lower half.

Frequently asked questions

Is Rombobox free?

Yes. You play it for free in your browser, with no downloads or sign-up. It is supported by ads.

Does it work on mobile?

Yes. It adapts to phones, tablets and computers. On a phone you play with four touch panels on the lower half of the screen, within thumb reach: the side ones to go left or right, and the middle ones to go up or down. On a computer you play with the arrow pad or your keyboard's arrow keys.

Is my progress saved?

Your streak, thinking time and Momentum are saved in your own browser. If you clear the site data, you start from scratch.

What happens if I reload the page or leave in the middle of a game?

The game counts as abandoned, just like a loss: your streak goes back to 0. That way nobody can swap boards when they get a hard one.

Do all boards have a solution?

Yes. Before showing you a board, the game computes the shortest possible path. If a board had no solution, it would be shuffled again.