Guide
How to Play Triangles
Triangles is a game of reading geometry and counting your options. Draw a legal line between two points, claim every triangle you complete, and take another turn for every capture.
Play TrianglesThe objective
Claim more triangles than your opponent
Triangles is played on a board of scattered points — no grid, no fixed pattern. You win by claiming more triangles than your opponent by the time no legal line remains anywhere on the board.
Between the deal and the final tally, the work is reading which lines are still safe to draw and which ones hand your opponent a free capture. There is no timer forcing your hand; the challenge is which line you choose, and when.
The game is free, runs in the browser, and needs no account. Open the board when you want to play; use this guide for the rules, both modes, and the habits that win more matches.
The board
14 to 18 points, no lines yet
Every match starts with a fresh scatter of 14 to 18 points placed with enough spacing to keep every line easy to read. Nothing is connected yet, and Player 1 — you, on a Vs. Computer board — always draws first.
Every board is a new layout. Some open up more capture chains than others, and you cannot always tell which is which before the lines start going down — that uncertainty is part of the game.
Controls
Drag, tap, or use the keyboard
Every method draws the same line. Pick whichever fits the device in your hand.
Mouse & touch
Drag between two points
Press on a point and drag toward another. A line previews as you move and turns red over an illegal target. Release on a valid point to draw it.
Touch-friendly
Tap, then tap again
Tap a point to select it — it lights up — then tap a second point to connect them. Tap the selected point again, or tap empty space, to cancel.
Desktop
Keyboard
Tab cycles through the points, Enter or Space selects one and then connects it to the next, Escape clears a selection, N deals a new board, and M mutes the sound.
The loop
Four steps you repeat all match
Reading the board, then choosing your line, is the whole game.
- 1
Read the board
A fresh board scatters 14 to 18 points at random — no grid, no fixed pattern. There are no lines yet. Player 1 (you, against the computer) always draws first.
- 2
Draw a legal line
On your turn, connect any two points with a straight line. The only rules: the line cannot already exist, cannot cross another line, and cannot pass through a third point — no matter how far apart the two points are or how many other points sit between them.
- 3
Claim the triangles you complete
The instant your line leaves three points fully connected to each other, you claim that triangle and its color fills in. If one line closes more than one triangle at once, you claim all of them.
- 4
Take your extra turn — or pass it on
Completing at least one triangle earns you another turn immediately, so a good line can chain into several in a row. A line that completes nothing passes play to the other side. The match ends when no two points can be legally connected; most triangles wins.
Rules & scoring
Every rule that decides a line
The objective
Claim more triangles than your opponent. The match is decided the moment no legal line remains anywhere on the board.
What makes a line legal
A line joins two points that are not already connected. It may not cross any existing line, and it may not pass through a third point. Short or long, a line is legal purely by those two tests — there is no limit on how far apart the two points can be.
Claiming a triangle
A triangle is claimed the instant three points become fully connected to one another — all three sides drawn. Whoever draws the third side owns the triangle, even if the other two sides were drawn by different players on different turns.
The extra-turn chain
Completing one or more triangles on a line keeps the turn with the same player, so a single turn can run through several lines in a row if each one closes another triangle. The turn passes only when a drawn line completes nothing.
Ending the match
The match ends automatically once every remaining pair of points would require a line that crosses another line or passes through a point. Count the triangles: more wins, an equal split is a draw. There is no separate scoring beyond the triangle count.
Match modes
Vs. Computer or Vs. a friend
Pick the mode on the deal screen; stats are kept separately for each.
- 01 · Easy, Normal, or Hard
Vs. Computer
Play a computer opponent that always takes a free triangle on Normal and Hard, and on Hard also reads one move ahead to avoid handing you an easy chain and to minimize any forced sacrifice. Easy plays loosely and will occasionally miss an obvious capture.
- 02 · Pass-and-play, same screen
Vs. a friend
Hand the device back and forth on one board. Player 1 and Player 2 take alternating turns exactly as against the computer, with no separate accounts and nothing to configure beyond who goes first.
Common mistakes
Why close matches get lost
Adding the second side too early
Drawing the second side of a triangle before you are forced to gives your opponent a free capture next turn. Play elsewhere on the board until that line is unavoidable.
Grabbing every triangle in sight
A lone triangle looks tempting, but the line that claims it sometimes opens a bigger chain for your opponent right after. Check what your capturing line exposes before you draw it.
Losing count in the endgame
Late in a match, whoever runs out of safe lines first has to sacrifice. Not tracking how many safe moves remain is the single most common way to lose a close match.
Drawing long lines out of habit
A line spanning the whole board is not inherently stronger than a short one. Every line is judged only by which triangles it sets up or completes, never by how much of the board it crosses.
- Take a free triangle the moment a line offers one — passing it up only hands your opponent the initiative.
- Before you draw, check whether your line leaves two sides of some other triangle in place, ready for your opponent to finish next turn.
- When every remaining line sets up a triangle for someone, count the safe lines left — the player who runs out of safe moves first is the one forced to sacrifice.
- If you must sacrifice, look for the smallest giveaway — one triangle is far better than opening a chain of three or four connected ones.
- Watch for chains: a run of points each missing only their outer connection can cascade, handing several triangles to whoever completes the first one.
- Lines through the crowded middle of the board tend to touch more potential triangles than lines along the edge — treat them with more caution.
- When a chain of captures gives you a run of extra turns, use the last one to leave the safest position on the board, not just to grab the last triangle in sight.
Where you can play
Same game on phone and desktop
trianglegame.app runs in any modern browser with no app to install. Progress stays on the device you played on.
Desktop browsers
Chrome, Edge, Firefox, and Safari all run the game with no plugin. Drag between points with the mouse, or use Tab and Enter to select and connect from the keyboard.
Phones and tablets
The board and both players’ scores stay on one screen in portrait. Drag a line with your finger, or tap a point and tap a second one to connect — restart is instant, with no page reload.
Progress on this device
Wins, losses, draws, longest win streak, and best winning margin are tracked separately for each computer difficulty and for pass-and-play, saved in local browser storage. They stay until you reset them or clear site data, and do not sync between devices.
Still stuck on a rule? Read the Triangles FAQ or jump in and play.
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