diff --git a/Grammar.cf b/Grammar.cf
index 6870367..da285a0 100644
--- a/Grammar.cf
+++ b/Grammar.cf
@@ -17,7 +17,8 @@ ELet.   Exp  ::= "let" Ident "=" Exp "in" Exp ;
 EAbs.   Exp  ::= "\\" Ident "." Exp ;
 ECase.  Exp ::= "case" Exp "of" "{" [Inj]  "}";
 
-LInt. Literal ::= Integer ;
+LInt.  Literal ::= Integer ;
+LBool. Literal ::= "Ture" ;
 
 Inj. Inj ::= Init "=>" Exp ;
 terminator Inj ";" ;
diff --git a/src/Monomorpher/MonomorpherIr.hs b/src/Monomorpher/MonomorpherIr.hs
index 14c82ae..01fac01 100644
--- a/src/Monomorpher/MonomorpherIr.hs
+++ b/src/Monomorpher/MonomorpherIr.hs
@@ -83,6 +83,7 @@ instance Print Exp where
   prt i = \case
     EId n       -> prPrec i 3 $ concatD [prtId 0 n]
     ELit _ (LInt i1) -> prPrec i 3 $ concatD [prt 0 i1]
+    ELit _ LBool -> prPrec i 0 (concatD [doc (showString "Ture")])
     ELet bs e    -> prPrec i 3 $ concatD
                     [ doc $ showString "let"
                     , prt 0 bs
diff --git a/src/TypeChecker/TypeCheckerIr.hs b/src/TypeChecker/TypeCheckerIr.hs
index c85ebcc..7b0e445 100644
--- a/src/TypeChecker/TypeCheckerIr.hs
+++ b/src/TypeChecker/TypeCheckerIr.hs
@@ -69,6 +69,7 @@ instance Print Exp where
   prt i = \case
     EId n       -> prPrec i 3 $ concatD [prtId 0 n]
     ELit _ (LInt i1) -> prPrec i 3 $ concatD [prt 0 i1]
+    ELit _ LBool ->     prPrec i 0 (concatD [doc (showString "Ture")])
     ELet bs e    -> prPrec i 3 $ concatD
                     [ doc $ showString "let"
                     , prt 0 bs
diff --git a/tests/Tests.hs b/tests/Tests.hs
index de9ab7c..edfd90b 100644
--- a/tests/Tests.hs
+++ b/tests/Tests.hs
@@ -22,9 +22,25 @@ main = do
 
 -- A simple demo
 simpleDemo = do
-  demo "main = f 5" $ simpleProgram [f] "f" 5
-  demo "main = p 5" $ simpleProgram [p] "p" 5
-  demo "main = g 5" $ simpleProgram [g, p] "g" 5
+  demo "main = f 5" $ simpleProgram [f] 
+    (mainApp (T.EId ("f", typeIntToInt)) lit5)
+  demo "main = bigId 5" $ simpleProgram [bigId] 
+    (mainApp (T.EId ("bigId", typeIntToInt)) lit5)
+  demo "main = g 5" $ simpleProgram [g, bigId] 
+    (mainApp (T.EId ("g", typeIntToInt)) lit5)
+  demo "main = (bigConst 5) ((bigConst 5) True)" $ simpleProgram [bigConst]
+    (T.EApp typeInt
+      -- (bigConst 5)
+      (T.EApp typeIntToInt (T.EId ("bigConst", typeIntToIntToInt)) lit5)
+      -- ((bigConst 5) True)
+      (T.EApp typeInt
+        (T.EApp typeBoolToInt
+          (T.EId ("bigConst", typeIntToBoolToInt))
+          lit5
+        )
+        litTrue
+      ) 
+    )
 
 -- Nice demo 👍
 demo :: String -> T.Program -> IO ()
@@ -37,31 +53,60 @@ demo label prg = do
   printToErr "##########\n"
 
 -- Programs in the form of "main = 'func' 'x'"
-simpleProgram :: [T.Bind] -> T.Ident -> Int -> T.Program
-simpleProgram binds fToCall input = T.Program (T.Bind ("main", typeInt) [] (simpleProgramExp fToCall):binds)
-simpleProgramExp func = T.EApp typeInt (T.EId (func, typeIntToInt)) (T.ELit typeInt $ LInt 5)
+simpleProgram :: [T.Bind] -> T.Exp -> T.Program
+simpleProgram binds input = T.Program (T.Bind ("main", typeInt) [] input:binds)
+
+-- Applies two expressions, has type Int
+mainApp :: T.Exp -> T.Exp -> T.Exp
+mainApp = T.EApp typeInt
 
 -- f :: Int -> Int
 -- f x = x + x
 f = T.Bind ("f", typeIntToInt) [("x", typeInt)] fExp
-fExp = T.EAdd typeInt (T.EId ("x", typeInt)) (T.EId (Ident "x", typeInt))
+fExp = T.EAdd typeInt (T.EId ("x", typeInt)) (T.EId ("x", typeInt))
 
--- p :: a -> a
--- p x = x + x
-p = T.Bind (Ident "p", typeAToA) [(Ident "x", typeA)] pExp
-pExp = T.EAdd typeA (T.EId (Ident "x", typeA)) (T.EId (Ident "x", typeA))
+-- bigId :: a -> a
+-- bigId x = x
+bigId = T.Bind (Ident "bigId", typeAToA) [(Ident "x", typeA)] bigIdExp
+bigIdExp = T.EAdd typeA (T.EId (Ident "x", typeA)) (T.EId ("x", typeA))
+
+-- bigConst :: a -> a -> a
+-- bigConst x y = x
+bigConst = T.Bind ("bigConst", typeAToAToA) [("x", typeA), ("y", typeA)] bigConstExp
+bigConstExp = T.EId ("x", typeA)
 
 -- g :: a -> a
--- g x = x + (p x)
-g = T.Bind (Ident "g", typeAToA) [("x", typeA)] gExp
-gExp = T.EAdd typeA (T.EId (Ident "x", typeA)) (T.EApp typeA (T.EId (Ident "p", typeAToA)) (T.EId (Ident "x", typeA)))
+-- g x = x + (bigId x)
+g = T.Bind ("g", typeAToA) [("x", typeA)] gExp
+gExp = T.EAdd typeA (T.EId ("x", typeA)) (T.EApp typeA (T.EId ("bigId", typeAToA)) (T.EId ("x", typeA)))
 
 -- | Reusable test constructs for Monomorpher.
-typeInt = T.TMono $ Ident "Int"
+typeInt = T.TMono "Int"
 
 typeIntToInt = T.TArr typeInt typeInt
 
+typeIntToIntToInt = T.TArr typeInt typeIntToInt
+
+
 typeA = T.TPol $ Ident "a"
 
 typeAToA = T.TArr typeA typeA
 
+typeAToAToA = T.TArr typeA typeAToA
+
+
+typeBool = T.TMono "Bool"
+
+typeBoolToBool = T.TArr typeBool typeBool
+
+typeBoolToBoolToBool = T.TArr typeBool typeBoolToBool
+
+
+lit5 = T.ELit typeInt $ T.LInt 5
+
+litTrue = T.ELit typeBool T.LBool
+
+
+typeBoolToInt = T.TArr typeBool typeInt
+typeIntToBoolToInt = T.TArr typeInt typeBoolToInt
+