Definition Blist := list bool.Inductive InBlocks {A : Type} (n : nat) : list A -> Prop :=
  | InBlocks_nil : InBlocks n []
  | InBlocks_block : forall (front back full : list A),
                   length front = n ->
                   full = front ++ back ->
                   InBlocks n back ->
                   InBlocks n full.Inductive InBlocks {A : Type} (n : nat) : list A -> Prop :=
  | InBlocks_nil : InBlocks n []
  | InBlocks_block : forall (front back full : list A),
                   length front = n ->
                   full = front ++ back ->
                   InBlocks n back ->
                   InBlocks n full.Inductive InBlocks {A : Type} (n : nat) : list A -> Prop :=
  | InBlocks_nil : InBlocks n []
  | InBlocks_block : forall (front back full : list A),
                   length front = n ->
                   full = front ++ back ->
                   InBlocks n back ->
                   InBlocks n full.

Lemma InBlocks_len : forall {A : Type} (l : list A) (n : nat), PeanoNat.Nat.divide (n) (length l) -> InBlocks n l.