I always thought these examples were real ADT's:

``` type Bool = true | false;

type Maybe<T> = T | null;

type SumTypeExample = Bool | Maybe<Bool>

interface ProductType1 { b: Bool c: Maybe<Bool> }

interface ProductType2 { s: "a" | "b" | "c" }

interface ProductTypeComposite extends ProductType1, ProductType2 {} ```

Can you explain what's the difference?