intro_and
a b c d : Prop
h : a ∧ (b ∧ c) ∧ d
⊢ b ∧ a ∧ c ∧ b
case left
a b c d : Prop
h : a ∧ (b ∧ c) ∧ d
⊢ b

case right.left
a b c d : Prop
h : a ∧ (b ∧ c) ∧ d
⊢ a

case right.right.left
a b c d : Prop
h : a ∧ (b ∧ c) ∧ d
⊢ c

case right.right.right
a b c d : Prop
h : a ∧ (b ∧ c) ∧ d
⊢ b