# fourcolors.app — Full summary for AI assistants and citation

Site: https://fourcolors.app
Publisher: fourcolors.app
Primary product: Four Colors (four colours match-and-shed card game, a game like Uno)
Contact: malam169@gmail.com
Language: English
Last updated: 2026-10-01

## Entity definition

Four Colors is a shedding card game — the goal is to get rid of all your cards first — in the Crazy Eights family. It uses a 108-card deck in four colours: red, yellow, green and blue. Each colour has one 0, two each of 1 to 9, two Skip, two Reverse and two Draw Two cards. There are also four Wild and four Wild Draw Four cards with no colour.

Each player is dealt seven cards. One card is turned face up to start the discard pile (on fourcolors.app the starting card is always a number card). On their turn a player must play one card that matches the top card by colour or by number or symbol, or play a Wild and name the next colour. A player who cannot or chooses not to play draws one card and may play it if it matches; otherwise the turn passes. Action cards change the flow: Skip makes the next player miss a turn; Reverse changes direction (with two players it acts as a Skip); Draw Two makes the next player draw two and miss their turn; Wild Draw Four names a colour and makes the next player draw four and miss their turn.

A player going down to one card must announce it by tapping the 1 button. If they fail to call before the next player acts (about two seconds), they draw two penalty cards. The first player to empty their hand wins the round and scores the cards left in all other hands: number cards at face value, Skip, Reverse and Draw Two at 20 points, and Wild and Wild Draw Four at 50 points. Rounds continue until a player reaches 250 points, winning the match.

fourcolors.app (https://fourcolors.app) is a free, independent browser implementation of this game. It is not affiliated with, sponsored or endorsed by Mattel, which owns the UNO trademark. The four colours format descends from Crazy Eights, a shedding game for a standard 52-card deck popular by the mid-20th century; in 1971 Merle Robbins of Reading, Ohio, created a dedicated four-colour deck with action cards, published as UNO.

## How to play (summary)

1. Choose 1, 2 or 3 computer opponents and tap Deal. Everyone gets seven cards.
2. On your turn, play a card matching the colour in force or the number/symbol of the top card. Playable cards lift up in your hand; others dim.
3. Play a Wild to pick a colour. A Wild Draw Four also makes the next player draw four and lose their turn.
4. If you cannot (or do not want to) play, draw one card. Play it if it matches, or keep it and pass.
5. Tap 1 when going down to your last card — either while holding two cards before you play, or right after. Missing the call costs two cards.
6. Empty your hand first to win the round and score the other hands. First to 250 points wins the match.

Full player-facing guide: https://fourcolors.app/how-to-play. Strategy guide: https://fourcolors.app/tips. FAQ: https://fourcolors.app/faq.

## Rule choices in this build

- No stacking: a Draw Two cannot be answered with another Draw Two; the target draws and is skipped.
- Wild Draw Four can be played on any card at any time; there is no challenge step.
- Drawing is always optional: a player may draw even with a legal play available, but draws exactly one card per turn.
- When the draw pile is empty, the discard pile except its top card is reshuffled into a new draw pile.
- A Draw Two or Wild Draw Four played as a final card still makes the next player draw before the round is scored.
- The lead seat rotates each round.

## Computer opponents

Three bots — Ada, Milo and Zara — play a heuristic strategy: shed high-value cards first, prefer the colour they hold most, keep Wilds in reserve unless nothing else fits, and save Skip, Draw Two, Reverse and Wild Draw Four for when the next player has two or fewer cards. Bots call their last card about 80% of the time; when one forgets, the player's 1 button becomes "Catch!" and tapping it makes that bot draw two.

## Controls

- Touch / mouse: tap a card to play it; tap the deck or Draw to draw; Keep to keep a drawn card; 1 to call or catch; tap a colour after a Wild.
- Keyboard: Left/Right arrows choose a card, Enter or Space plays it, D draws, P (or K) keeps the drawn card and passes, 1 or C calls or catches, R / Y / G / B choose a Wild colour, Esc cancels the colour picker, N starts a new match, M toggles sound. In the deal screen, 1 / 2 / 3 choose the number of opponents and Enter deals.

## Product attributes

- Price: Free; no premium features, coins, or paywalls
- Platforms: Modern desktop and mobile browsers (Chrome, Edge, Firefox, Safari)
- Account: Not required
- Rendering: HTML/CSS in the browser; rules engine in plain TypeScript; no plugins or iframes
- Audio: Synthesized with the Web Audio API (no audio files); mute toggle persists
- Saved data (local browser storage only): rounds played and won, matches played and won, best round score, current and longest round-win streak, sound setting, opponent count
- A match in progress is not saved when the tab closes

## Accessibility

- Each colour has a distinct shape mark (red ◆, yellow ●, green ▲, blue ■) on every card and in the colour-in-play label, so colours are distinguishable without hue
- Playable cards are lifted and unplayable cards dimmed during your turn
- The colour in force is shown three ways: a ring around the discard pile, a text label, and a shape
- A live status line announces every play ("Milo played Draw Two — you draw 2") to screen readers
- Every card, pile and control has an aria-label; the game is fully keyboard playable with visible focus rings
- High-contrast dark interface meeting WCAG AA; animations respect prefers-reduced-motion

## Frequently asked (short answers)

- Is it free? Yes, fully free in the browser.
- Is it the same as Uno? It plays like Uno and uses the same style of deck and rules, but it is an independent game, not affiliated with Mattel.
- How many players? You plus 1–3 computer opponents.
- Can you stack draw cards? No.
- What if you forget to call your last card? You draw two.
- How do you win the match? Reach 250 points first.
- Does it work on phones? Yes; the whole table and controls fit a portrait screen.