∀ {C₁ : Type u_5} {C₂ : Type u_6} {C₃ : Type u_7} {C₄ : Type u_8} [inst : CategoryTheory.Category.{u_1, u_5} C₁]
  [inst_1 : CategoryTheory.Category.{u_2, u_6} C₂] [inst_2 : CategoryTheory.Category.{u_3, u_7} C₃]
  [inst_3 : CategoryTheory.Category.{u_4, u_8} C₄] {T : CategoryTheory.Functor C₁ C₂} {L : CategoryTheory.Functor C₁ C₃}
  {R : CategoryTheory.Functor C₂ C₄} {B : CategoryTheory.Functor C₃ C₄} (w : CategoryTheory.TwoSquare T L R B) {X₂ : C₂}
  {X₃ : C₃} (g : R.obj X₂ ⟶ B.obj X₃) (x : w.CostructuredArrowDownwards g),
  CategoryTheory.StructuredArrow.homMk
      (CategoryTheory.CostructuredArrow.homMk (CategoryTheory.CategoryStruct.id x).left.right ⋯) ⋯ =
    CategoryTheory.StructuredArrow.homMk
      (CategoryTheory.CostructuredArrow.homMk (CategoryTheory.CategoryStruct.id x).left.right ⋯) ⋯