diff --git a/Egison.hs b/Egison.hs
--- a/Egison.hs
+++ b/Egison.hs
@@ -9,7 +9,7 @@
 import IO hiding (try)
 
 welcomeMsg :: String
-welcomeMsg = "Egison, version 0.3.0.2 : http://hagi.is.s.u-tokyo.ac.jp/~egi/egison/\nWelcome to Egison Interpreter!\n"
+welcomeMsg = "Egison, version 0.3.0.3 : http://hagi.is.s.u-tokyo.ac.jp/~egi/egison/\nWelcome to Egison Interpreter!\n"
 
 byebyeMsg :: String
 byebyeMsg = "\nLeaving Egison.\nByebye. See you again! (^^)/\n"
diff --git a/egison.cabal b/egison.cabal
--- a/egison.cabal
+++ b/egison.cabal
@@ -7,7 +7,7 @@
 -- The package version. See the Haskell package versioning policy
 -- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
 -- standards guiding when and how versions should be incremented.
-Version:             0.3.0.2
+Version:             0.3.0.3
 
 -- A short (one-line) description of the package.
 Synopsis:            An Interpreter for the Programming Language Egison
@@ -15,7 +15,7 @@
 -- A longer description of the package.
 Description:         An interpreter for the programming language Egison.
                      A feature of Egison is the strong pattern match facility.
-                     With Egison, you can represent pattern matching for non-inductive data intuitively,
+                     With Egison, you can represent pattern matching for unfree data intuitively,
                      especially for collection data, such as lists, multisets, sets, and so on.
                      This package include sample Egison program codes "*-test.egi" in "etc/sample/" directory.
                      This package also include Emacs Lisp file "egison-mode.el" in "etc/elisp/" directory.
@@ -45,7 +45,7 @@
 
 Data-Dir:            etc/
 
-Data-files:          lib/base.egi lib/number.egi lib/collection.egi sample/number-test.egi sample/collection-test.egi sample/io-test.egi elisp/egison-mode.el
+Data-files:          lib/base.egi lib/number.egi lib/collection.egi lib/poker-hands.egi sample/number-test.egi sample/collection-test.egi sample/io-test.egi elisp/egison-mode.el
 
 -- Extra files to be distributed with the package, such as examples or
 -- a README.
diff --git a/etc/lib/base.egi b/etc/lib/base.egi
--- a/etc/lib/base.egi
+++ b/etc/lib/base.egi
@@ -1,7 +1,6 @@
 (define $Something
   (type
-    {[$var-match (lambda [$tgt] {tgt})]
-     }))
+    {[$var-match (lambda [$tgt] {tgt})]}))
 
 (define $Bool
   (type
@@ -13,15 +12,13 @@
            [_ {}]}]
          [false []
           {[<false> {[]}]
-           [_ {}]}]
-         })]
+           [_ {}]}]})]
      [$equal?
       (lambda [$val $tgt]
         (match [val tgt] [Bool Bool]
           {[[<true> <true>] <true>]
            [[<false> <false>] <true>]
-           [[_ _] <false>]}))]
-     }))
+           [[_ _] <false>]}))]}))
 
 (define $or
   (lambda [$b1 $b2]
@@ -54,13 +51,11 @@
            [_ {}]}]
          [greater []
           {[<greater> {[]}]
-           [_ {}]}]
-         })]
+           [_ {}]}]})]
      [$equal?
       (lambda [$val $tgt]
         (match [val tgt] [Order Order]
           {[[<less> <less>] <true>]
            [[<equal> <equal>] <true>]
            [[<greater> <greater>] <true>]
-           [[_ _] <false>]}))]
-     }))
+           [[_ _] <false>]}))]}))
diff --git a/etc/lib/collection.egi b/etc/lib/collection.egi
--- a/etc/lib/collection.egi
+++ b/etc/lib/collection.egi
@@ -6,16 +6,13 @@
         (deconstructor
           {[nil []
             {[{} {[]}]
-             [_ {}]
-             }]
+             [_ {}]}]
            [cons [a (List a)]
             {[{$x .$xs} {[x xs]}]
-             [_ {}]
-             }]
+             [_ {}]}]
            [snoc [a (List a)]
             {[{.$xs $x} {[x xs]}]
-             [_ {}]
-             }]
+             [_ {}]}]
            [join [(List a) (List a)]
             {[$tgt (let {[$loop
                        (lambda [$ts]
@@ -26,8 +23,7 @@
                               @(map (lambda [$as $bs]
                                       [{x @as} bs])
                                     (loop xs))}]}))]}
-                   (loop tgt))]
-             }]
+                   (loop tgt))]}]
            [nioj [(List a) (List a)]
             {[$tgt (let {[$loop
                        (lambda [$ts]
@@ -38,17 +34,12 @@
                               @(map (lambda [$as $bs]
                                       [{@as x} bs])
                                     (loop xs))}]}))]}
-                   (loop tgt))]
-             }]
-           })]
+                   (loop tgt))]}]})]
        [$equal? (lambda [$val $tgt]
                   (match [val tgt] [(List a) (List a)]
                     {[[<nil> <nil>] <true>]
-                     [[<cons $x $xs>
-                       <cons ,x ,xs>]
-                      <true>]
-                     [[_ _] <false>]}))]
-       })))
+                     [[<cons $x $xs> <cons ,x ,xs>] <true>]
+                     [[_ _] <false>]}))]})))
 
 (define $map
   (lambda [$fn $ls]
@@ -100,8 +91,7 @@
        [<cons $x $rs>
         (let {[$subs (subcollections rs)]}
           {@subs @(map (lambda [$sub] {x @sub})
-                       subs)})]
-       })))
+                       subs)})]})))
 
 (define $car
   (lambda [$xs]
@@ -121,8 +111,7 @@
       (match ys (List a)
         {[<nil> <false>]
          [<cons ,x $ys> <true>]
-         [<cons $y $ys> ((member? a) x ys)]
-         }))))
+         [<cons $y $ys> ((member? a) x ys)]}))))
 
 (define $unique
   (lambda [$a]
@@ -134,8 +123,7 @@
                          (match ((member? a) x ys) Bool
                            {[<true> (loop rs ys)]
                             [<false> (loop rs {@ys x})]
-                            [_ {}]
-                            })]}))]}
+                            [_ {}]})]}))]}
         (loop xs {})))))
 
 (define $subcollection?
@@ -162,25 +150,18 @@
         (deconstructor
           {[nil []
             {[{} {[]}]
-             [_ {}]
-             }]
+             [_ {}]}]
            [cons [a (Multiset a)]
             {[$tgt (map (lambda [$t] [t ((remove a) tgt t)])
-                        tgt)]
-             }]
+                        tgt)]}]
            [join [(Multiset a) (Multiset a)]
             {[$tgt (map (lambda [$ts] [ts ((remove-collection a) tgt ts)])
-                        (subcollections tgt))]
-             }]
-           })]
+                        (subcollections tgt))]}]})]
        [$equal? (lambda [$val $tgt]
                   (match [val tgt] [(Multiset a) (Multiset a)]
                     {[[<nil> <nil>] <true>]
-                     [[<cons $x $xs>
-                       <cons ,x ,xs>]
-                      <true>]
-                     [[_ _] <false>]}))]
-       })))
+                     [[<cons $x $xs> <cons ,x ,xs>] <true>]
+                     [[_ _] <false>]}))]})))
 
 (define $Set
   (lambda [$a]
@@ -199,7 +180,6 @@
             {[$tgt (let {[$tgt2 ((unique a) tgt)]}
                      (concat (map (lambda [$xs $ys] (map (lambda [$sxs] [xs {@ys @sxs}])
                                                          (subcollections xs)))
-                                  (match-all tgt2 (Multiset a) [<join $xs $ys> [xs ys]]))))]}]
-           })]
-       [$equal? (lambda [$val $tgt] (and ((subcollection? a) val tgt) ((subcollection? a) tgt val)))]
-       })))
+                                  (match-all tgt2 (Multiset a) [<join $xs $ys> [xs ys]]))))]}]})]
+       [$equal? (lambda [$val $tgt]
+                  (and ((subcollection? a) val tgt) ((subcollection? a) tgt val)))]})))
diff --git a/etc/lib/number.egi b/etc/lib/number.egi
--- a/etc/lib/number.egi
+++ b/etc/lib/number.egi
@@ -4,6 +4,8 @@
      [$equal? (lambda [$val $tgt]
                 (= val tgt))]}))
 
+(define $Int Number)
+
 (define $Nat
   (type
     {[$var-match (lambda [$tgt] {tgt})]
@@ -11,15 +13,11 @@
       (deconstructor
         {[o []
           {[0 {[]}]
-           [_ {}]
-           }]
+           [_ {}]}]
          [s [Nat]
           {[$tgt (match (compare-number tgt 0) Order
                    {[<greater> {(- tgt 1)}]
-                    [_ {}]})]
-           }]
-         })]
+                    [_ {}]})]}]})]
      [$equal? (lambda [$val $tgt]
-                (= val tgt))]
-     }))
+                (= val tgt))]}))
 
diff --git a/etc/lib/poker-hands.egi b/etc/lib/poker-hands.egi
new file mode 100644
--- /dev/null
+++ b/etc/lib/poker-hands.egi
@@ -0,0 +1,124 @@
+(define $Suit
+  (type
+    {[$var-match (lambda [$tgt] {tgt})]
+     [$inductive-match
+      (deconstructor
+        {[spade []
+          {[<spade> {[]}]
+           [_ {}]}]
+         [heart []
+          {[<heart> {[]}]
+           [_ {}]}]
+         [club []
+          {[<club> {[]}]
+           [_ {}]}]
+         [diamond []
+          {[<diamond> {[]}]
+           [_ {}]}]
+         })]
+     [$equal?
+      (lambda [$val $tgt]
+        (match [val tgt] [Suit Suit]
+          {[[<spade> <spade>] <true>]
+           [[<heart> <heart>] <true>]
+           [[<club> <club>] <true>]
+           [[<diamond> <diamond>] <true>]
+           [[_ _] <false>]}))]
+     }))
+
+(define $Mod
+  (lambda [$m]
+    (type
+      {[$var-match (lambda [$tgt] {(mod tgt m)})]
+       [$equal? (lambda [$val $tgt]
+                  (= (mod val m) (mod tgt m)))]})))
+
+(define $Card
+  (type
+    {[$var-match (lambda [$tgt] {tgt})]
+     [$inductive-match
+      (deconstructor
+        {[card [Suit (Mod 13)]
+          {[<card $s $n> {[s n]}]}]})]
+     [$equal? (lambda [$val $tgt]
+                (match [val tgt] [Card Card]
+                  {[[<card $s $n>
+                     <card ,s ,n>]
+                    <true>]
+                   [[_ _] <false>]}))]}))
+
+(define $poker-hands
+  (lambda [$Cs]
+    (match Cs (Multiset Card)
+      {[<cons <card $S $n>
+         <cons <card ,S ,(- n 1)>
+          <cons <card ,S ,(- n 2)>
+           <cons <card ,S ,(- n 3)>
+            <cons <card ,S ,(- n 4)>
+             !<nil>
+             >>>>>
+        <straight-flush>]
+       [<cons <card _ $n>
+         <cons <card _ ,n>
+          !<cons <card _ ,n>
+            !<cons <card _ ,n>
+              !<cons _
+                !<nil>
+                >>>>>
+        <four-of-kind>]
+       [<cons <card _ $m>
+         <cons <card _ ,m>
+          <cons <card _ ,m>
+           !<cons <card _ $n>
+             !<cons <card _ ,n>
+               !<nil>
+               >>>>>
+        <full-house>]
+       [<cons <card $S _>
+         !<cons <card ,S _>
+           !<cons <card ,S _>
+             !<cons <card ,S _>
+               !<cons <card ,S _>
+                 !<nil>
+                 >>>>>
+        <flush>]
+       [<cons <card _ $n>
+         <cons <card _ ,(- n 1)>
+          <cons <card _ ,(- n 2)>
+           <cons <card _ ,(- n 3)>
+            <cons <card _ ,(- n 4)>
+             !<nil>
+             >>>>>
+        <straight>]
+       [<cons <card _ $n>
+         <cons <card _ ,n>
+          <cons <card _ ,n>
+           <cons _
+            <cons _
+             !<nil>
+             >>>>>
+        <three-of-kind>]
+       [<cons <card _ $m>
+         <cons <card _ ,m>
+          !<cons <card _ $n>
+            <cons <card _ ,n>
+             !<cons _
+               !<nil>
+               >>>>>
+        <two-pair>]
+       [<cons <card _ $n>
+         <cons <card _ ,n>
+          <cons _
+           <cons _
+            <cons _
+             !<nil>
+             >>>>>
+        <one-pair>]
+       [<cons _
+         <cons _
+          <cons _
+           <cons _
+            <cons _
+             !<nil>
+             >>>>>
+        <nothing>]})))
diff --git a/etc/sample/collection-test.egi b/etc/sample/collection-test.egi
--- a/etc/sample/collection-test.egi
+++ b/etc/sample/collection-test.egi
@@ -55,8 +55,7 @@
           <cons <card ,S ,(- n 2)>
            <cons <card ,S ,(- n 3)>
             <cons <card ,S ,(- n 4)>
-             !<nil>
-             >>>>>
+             <nil>>>>>>
         <straight-flush>]
        [<cons <card _ $n>
          <cons <card _ ,n>
@@ -123,23 +122,12 @@
              >>>>>
         <nothing>]})))
 
-(define $ham1
-  (lambda [$xs $ys]
-    (match [xs ys] [(List Bool) (List Bool)]
-      {[[<join $hs <cons $x $ts>>
-         <join ,hs <cons ,(not x) ,ts>>]
-        <true>]
-       [[_ _] <false>]})))
 
-
-(test (match-all {1 2 3} (Multiset Number)
-        [<cons $x <cons $y <cons $z <nil>>>> [x y z]]))
-
 (test (match-all {{1 2 3} {4 5 1} {6 1 7}} (List (Multiset Number))
         [<cons <cons $x _>
-               <cons <cons $y _>
-                     <cons <cons $z _>
-                           <nil>>>>
+          <cons <cons $y _>
+           <cons <cons $z _>
+            <nil>>>>
          [x y z]]))
 
 (test (match-all {{1 2 3} {4 5 1} {6 1 7}} (List (Multiset Number))
@@ -284,3 +272,16 @@
 (test (match-all {1 2 3 4} (Stick Number) [<join $xs <cons $w $ys>> [xs w ys]]))
 (test (match-all {1 2 3} (Stick Number) [,{3 2 1} <ok>]))
 
+
+(match {2 7 7 2 7} (Multiset Number)
+  {[<cons $m
+     <cons ,m
+      <cons ,m
+       $tmp1>>>
+    (match tmp1 (Multiset Number)
+      {[<cons $n $tmp2>
+        (match tmp2 (Multiset Number)
+          {[<cons ,n $tmp3>
+            (match tmp3 (Multiset Number)
+              {[<nil> <ok>]})]})]})]
+   [_ <ko>]})