diff --git a/examples/count-forever.puyo b/examples/count-forever.puyo
new file mode 100644
index 0000000..96764a1
--- /dev/null
+++ b/examples/count-forever.puyo
@@ -0,0 +1,9 @@
+0 ->i
+
+(
+    i println
+    i 1 + ->i
+    loop!
+)->loop
+
+loop!
diff --git a/examples/foo.puyo b/examples/foo.puyo
new file mode 100644
index 0000000..79e9037
--- /dev/null
+++ b/examples/foo.puyo
@@ -0,0 +1,28 @@
+(70 put 105 put 122 put 122 put)→fizz
+(66 put 117 put 122 put 122 put)→buzz
+(10 put)→newline
+1→i
+
+(
+  i 15 % 0 =
+    (fizz! buzz!)
+    (
+      i 3 % 0 =
+        fizz
+        (
+          i 5 % 0 =
+            buzz
+            (i print)
+          ite
+        )
+      ite
+    )
+  ite
+  newline!
+  i 1 + →i
+  i 101 <
+    go
+    ()
+  ite
+)→go
+go!
diff --git a/examples/mandelbrot.puyo b/examples/mandelbrot.puyo
new file mode 100644
index 0000000..e291c9a
--- /dev/null
+++ b/examples/mandelbrot.puyo
@@ -0,0 +1,55 @@
+(
+  (
+  ->body
+  ->test
+  (
+    test!
+      (body! loop!)
+      ()
+    ite
+  )->loop
+  loop!
+  )!
+)->while
+
+-1.5 ->xmin
+0.47 ->xmax
+
+-1.12 ->ymin
+1.12 ->ymax
+
+27 ->itermax
+
+xmin ->x0
+ymin ->y0
+
+  (y0 ymax <)
+  (
+      (x0 xmax <)
+      (
+        0 ->x
+        0 ->y
+        0 ->iter
+
+          (x x * y y * + 4 < iter itermax < *)
+          (
+            x x * y y * - x0 + ->xtemp
+            2 x y * * y0 + ->y
+            xtemp ->x
+            iter 1 + ->iter
+          )
+        while!
+
+        iter itermax =
+          (32 put)
+          (64 iter + put)
+        ite
+        
+        x0 0.03 + ->x0
+      )
+    while!
+    10 put
+    y0 0.08 + ->y0
+    xmin ->x0
+  )
+while!
diff --git a/src/eval.rs b/src/eval.rs
index 51e2680..ab776d1 100644
--- a/src/eval.rs
+++ b/src/eval.rs
@@ -30,8 +30,8 @@ impl fmt::Display for Val<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Val::Num(n) => write!(f, "{n}"),
-            Val::Fun { insts, env: _ } => {
-                write!(f, "{}", Inst::Block(insts.to_vec()))
+            Val::Fun { insts, env } => {
+                write!(f, "{} {}", Inst::Block(insts.to_vec()), env.borrow())
             }
         }
     }
@@ -66,6 +66,26 @@ enum Env<'a> {
     },
 }
 
+impl fmt::Display for Env<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Env::Local(map) => {
+                for key in map.keys() {
+                    write!(f, "{key} ")?;
+                }
+                Ok(())
+            }
+            Env::Closure { local, above } => {
+                for key in local.keys() {
+                    write!(f, "{key} ")?;
+                }
+                write!(f, "| ")?;
+                write!(f, "{}", above.borrow())
+            }
+        }
+    }
+}
+
 impl Default for Env<'_> {
     fn default() -> Self {
         Env::Local(HashMap::new())
@@ -211,6 +231,8 @@ fn eval<'a>(insts: &'a [Inst<'a>], stack: &mut Stack<'a>, env: &Rc<RefCell<Env<'
                     for (i, val) in stack.0.iter().rev().enumerate() {
                         eprintln!("{}. {val}", i + 1);
                     }
+                    io::stdout().flush().unwrap();
+                    io::stderr().flush().unwrap();
                     process::exit(3);
                 }
                 "ite" => {