#### 3.1.2 Key and reserved words

The keywords of `sketch` are `picturebox` `curve` `def` `dots` `frame` `global` `input` `line` `polygon` `put` `repeat` `set` `sweep` and `then`. The `sketch` parser will note a syntax error if any of these are used in place of a proper identifier.

In addition, there are reserved words that can currently be defined by the user, but with the risk that future versions of `sketch` will reject those definitions. The reserved words are `acos` `asin` `atan2` `cos` `inverse` `perspective` `project` `rotate` `scale` `sin` `special` `sqrt` `translate` `unit` and `view`.