(motive : Option (Array Aesop.Script.SScript × Aesop.Script.SScript) → Sort u_1) →
  (x : Option (Array Aesop.Script.SScript × Aesop.Script.SScript)) →
    ((nested : Array Aesop.Script.SScript) → (tail : Aesop.Script.SScript) → motive (some (nested, tail))) →
      ((x : Option (Array Aesop.Script.SScript × Aesop.Script.SScript)) → motive x) → motive x