/// First the Feature Tree

/// Adding [*] before the feature name will make it Required
/// Adding [ ] before the feature name will mark it as Optional

/// Composite features can express constraints between their sub-features
/// { } a set of exclusive features (pick one)
/// ( ) any combination of the features is possible
/// [ ] a set of features (usually combined with the [*] [ ] annotation)

Product: [
    [*] Required Feature : {  
        Alternative Sub Feature1,
        Alternative Sub Feature1
    },
    [ ] Optional Feature : [
        [*] Required Sub Feature,
        [ ] Optional Sub Feature
    ],
    Combined Feature : (
        Sub Feature1,
        Sub Feature2
    )
]

/// Then the feature relationships

/// Implication
Sub Feature1 => Optional Sub Feature

/// Exclusive
Alternative Sub Feature1 <--> Sub Feature2