diff --git a/dags.mli b/dags.mli
new file mode 100644
index 0000000000000000000000000000000000000000..f006bdfa838bd0ebffb1cadec19f59259995f1c3
--- /dev/null
+++ b/dags.mli
@@ -0,0 +1,33 @@
+type nid = int
+type label = VarI of string | VarO of string | Const of string
+type port = nid * int option
+val map_port : ('a -> 'b) -> 'a * 'c -> 'b * 'c
+type 'a lidag = {
+  iports : port list;
+  oports : port list;
+  nodes : (nid * int * int) list;
+  edges : (port * port) list;
+  labels : (nid * label) list;
+  ibinders : nid list;
+  obinders : nid list;
+}
+val empty_dag : 'a lidag
+val anonym_link :
+  start:'a -> finish:'b -> ('a * 'c option) * ('b * 'd option)
+val mapids : (nid -> nid) -> 'a lidag -> 'b lidag
+val maxid : 'a lidag -> nid
+val sequence : first:'a lidag -> second:'b lidag -> 'c lidag
+val parallel : top:'a lidag -> bottom:'b lidag -> 'c lidag
+val ( >>= ) : 'a list -> ('a -> 'b list) -> 'b list
+val link : vars:(string * string) list -> dag:'a lidag -> 'b lidag
+val constant : name:string -> inputs:int -> outputs:int -> 'a lidag
+val ivar : name:string -> 'a lidag
+val ovar : name:string -> 'a lidag
+val identity : number:int -> 'a lidag
+val parallels : 'a lidag list -> 'a lidag
+val sequences : 'a lidag list -> 'a lidag
+val example_circuit : 'a lidag
+val tightening1 :
+  middle:'a lidag -> first:'b lidag -> last:'b lidag -> 'b lidag
+val tightening2 :
+  middle:'a lidag -> first:'a lidag -> last:'a lidag -> 'b lidag
diff --git a/dot.mli b/dot.mli
new file mode 100644
index 0000000000000000000000000000000000000000..1ce8cf8f2129fa1984846ec83ee9e553408bc193
--- /dev/null
+++ b/dot.mli
@@ -0,0 +1,55 @@
+module SM :
+  sig
+    type key = String.t
+    type 'a t = 'a Map.Make(String).t
+    val empty : 'a t
+    val is_empty : 'a t -> bool
+    val mem : key -> 'a t -> bool
+    val add : key -> 'a -> 'a t -> 'a t
+    val singleton : key -> 'a -> 'a t
+    val remove : key -> 'a t -> 'a t
+    val merge :
+      (key -> 'a option -> 'b option -> 'c option) -> 'a t -> 'b t -> 'c t
+    val union : (key -> 'a -> 'a -> 'a option) -> 'a t -> 'a t -> 'a t
+    val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
+    val equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
+    val iter : (key -> 'a -> unit) -> 'a t -> unit
+    val fold : (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
+    val for_all : (key -> 'a -> bool) -> 'a t -> bool
+    val exists : (key -> 'a -> bool) -> 'a t -> bool
+    val filter : (key -> 'a -> bool) -> 'a t -> 'a t
+    val partition : (key -> 'a -> bool) -> 'a t -> 'a t * 'a t
+    val cardinal : 'a t -> int
+    val bindings : 'a t -> (key * 'a) list
+    val min_binding : 'a t -> key * 'a
+    val max_binding : 'a t -> key * 'a
+    val choose : 'a t -> key * 'a
+    val split : key -> 'a t -> 'a t * 'a option * 'a t
+    val find : key -> 'a t -> 'a
+    val map : ('a -> 'b) -> 'a t -> 'b t
+    val mapi : (key -> 'a -> 'b) -> 'a t -> 'b t
+  end
+type dot = string
+type node_mod = string SM.t
+type uid = int
+val addPrelude : string -> string
+val count : int ref
+val uid : unit -> int
+val renderMods : string SM.t -> string
+val mod_shape : 'a -> 'a SM.t -> 'a SM.t
+val mod_color : 'a -> 'a SM.t -> 'a SM.t
+val mod_label : string -> string SM.t -> string SM.t
+val mod_style : string -> string SM.t -> string SM.t
+val mod_width : float -> string SM.t -> string SM.t
+val mod_height : float -> string SM.t -> string SM.t
+val mod_fixedsize : bool -> string SM.t -> string SM.t
+val mkLabel : int -> int option -> string -> string
+val mkNode : int -> string SM.t -> string
+val emptyMod : 'a SM.t
+val baseMod : string SM.t
+val inputsOutputs : string -> int -> int -> string SM.t -> string SM.t
+val mkLink : int -> int option -> int -> int option -> string
+val rank_group : string -> int list -> string
+val addDot : string -> string -> string
+val addDots : string list -> string
+val tests : 'a list