∀ {C₁ : Type u₁} {C₂ : Type u₂} {C₃ : Type u₃} {C₄ : Type u₄} [inst : CategoryTheory.Category.{v₁, u₁} C₁]
  [inst_1 : CategoryTheory.Category.{v₂, u₂} C₂] [inst_2 : CategoryTheory.Category.{v₃, u₃} C₃]
  [inst_3 : CategoryTheory.Category.{v₄, u₄} 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)
  {X₃ : C₃ᵒᵖ} {X₂ : C₂ᵒᵖ} (g : B.op.obj X₃ ⟶ R.op.obj X₂) (f : (w.op.StructuredArrowRightwards g)ᵒᵖ),
  ((CategoryTheory.TwoSquare.structuredArrowRightwardsOpEquivalence.functor w g).obj f).left.hom =
    (Opposite.unop f).right.hom.unop