∀ {X Y S : Type v} {f : X ⟶ S} {g : Y ⟶ S} {c : CategoryTheory.Limits.PullbackCone f g}
  (hc : CategoryTheory.Limits.IsLimit c) (x : CategoryTheory.Limits.Types.PullbackObj f g),
  c.snd ((CategoryTheory.Limits.PullbackCone.IsLimit.equivPullbackObj hc).symm x) = (↑x).2