Getter

Getters are used for getting, or reading, a value from a variable.

Setter

Setters are used for setting, or writing, a value to a variable.

Strings are pieces of text, or collections of characters.

Comments are used for leaving notes for other humans. They are ignored by the app.

A mutator is able to change the shape of a block. Examples include, join, +, and If

Data which can change in your app are know as variables.