# Variables

> Numbers, text, teams and timers that rules read and change - for the game, for each player or for each object.

Variables are what your game remembers: a score, a team, a timer.

![The Variables page: variables, enumerations and expressions as cards, with the elapsed timer selected in the Inspector.](/shots/variables-page.png)

## Make one

1. Open **Variables** and press **New variable**.
2. Name it, and pick its **Type** and **Scope**.

| Scope       | One value for  | Read it as     |
| ----------- | -------------- | -------------- |
| Game        | the whole game | `score`        |
| Each player | every player   | `player.score` |
| Each object | every object   | `ball.hits`    |

- **Starts at**: its first value.
- **Reset at match start**: turn off for settings that should stay, like a
  score limit.
- **Timer**: counts seconds by itself, while a condition holds or when rows
  start it.

## Enumerations

A short list of named values, like teams (`Red`, `Blue`) or phases
(`kickoff`, `playing`).

## Expressions

A formula with a name, such as `HasWinner`, used anywhere a value fits.

You never type formulas. You build them from blocks:

![The HasWinner formula as nested blocks: or, and, compare, max of RedScore and BlueScore.](/shots/expression-blocks.png)

| Block                 | Gives                                          |
| --------------------- | ---------------------------------------------- |
| **Value**             | A number, text, colour, point, yes or no       |
| **Read**              | A variable, a player, a line, a property       |
| **Math**, **Compare** | Two values joined: `plus`, `is at least`…      |
| **And / or**, **Not** | Conditions combined                            |
| **Choose**            | One value _when_ something holds, else another |
| **Function**          | `max`, `distance` and friends                  |
| **Count**             | How many players, instances…                   |

Each slot only offers blocks that fit it.

### Nothing and angles

- **Nothing spreads.** A block that reads something missing, such as a
  destroyed ball's speed, gives nothing. Maths, text and comparisons with
  nothing give nothing, so a visual bound to it isn't shown and a condition
  counts as false. `or` is true when either side is, and `and` false when
  either side is.
- **Otherwise** gives a value in place of nothing: _otherwise(Ball's speed, 0)_.
- **Is empty** asks the question directly: _winner = empty_.
- **Angles are in degrees** everywhere in Studio: rotations, arcs, and the
  `sin`, `cos`, `atan2`, `angleOf` and `fromAngle` functions.

## Live values

While Play runs, select a variable to see its value right now.