{- `build` is the inverse of `fold` Examples: ``` ./build (λ(bool : Type) → λ(true : bool) → λ(false : bool) → true) = True ./build (λ(bool : Type) → λ(true : bool) → λ(false : bool) → false) = False ``` -} let build : (∀(bool : Type) → ∀(true : bool) → ∀(false : bool) → bool) → Bool = λ(f : ∀(bool : Type) → ∀(true : bool) → ∀(false : bool) → bool) → f Bool True False in build