diff --git a/examples/ch1-01/hello/hello.go b/examples/ch1-01/hello/hello.go
deleted file mode 100644
index dbf73ed..0000000
--- a/examples/ch1-01/hello/hello.go
+++ /dev/null
@@ -1,10 +0,0 @@
-// Copyright © 2017 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-package main
-
-import "fmt"
-
-func main() {
-	fmt.Println("你好, 世界!")
-}
diff --git a/examples/ch1-02/hello-alef/hello.alef b/examples/ch1-02/hello-alef/hello.alef
deleted file mode 100644
index 6c864c8..0000000
--- a/examples/ch1-02/hello-alef/hello.alef
+++ /dev/null
@@ -1,19 +0,0 @@
-#include <alef.h>
-
-void receive(chan(byte*) c) {
-	byte *s;
-	s = <- c;
-	print("%s\n", s);
-	terminate(nil);
-}
-
-void main(void) {
-	chan(byte*) c;
-	alloc c;
-	proc receive(c);
-	task receive(c);
-	c <- = "hello proc or task";
-	c <- = "hello proc or task";
-	print("done\n");
-	terminate(nil);
-}
diff --git a/examples/ch1-02/hello-b/main.b b/examples/ch1-02/hello-b/main.b
deleted file mode 100644
index e77f5c3..0000000
--- a/examples/ch1-02/hello-b/main.b
+++ /dev/null
@@ -1,8 +0,0 @@
-main() {
-	extrn a, b, c;
-	putchar(a); putchar(b); putchar(c);
-	putchar('!*n');
-}
-a 'hell';
-b 'o, w';
-c 'orld';
diff --git a/examples/ch1-02/hello-c-01/hello-c-01.c b/examples/ch1-02/hello-c-01/hello-c-01.c
deleted file mode 100644
index 5144cb4..0000000
--- a/examples/ch1-02/hello-c-01/hello-c-01.c
+++ /dev/null
@@ -1,4 +0,0 @@
-main()
-{
-	printf("hello, world");
-}
diff --git a/examples/ch1-02/hello-c-02/hello-c-02.c b/examples/ch1-02/hello-c-02/hello-c-02.c
deleted file mode 100644
index eaab7bb..0000000
--- a/examples/ch1-02/hello-c-02/hello-c-02.c
+++ /dev/null
@@ -1,4 +0,0 @@
-main()
-{
-	printf("hello, world\n");
-}
diff --git a/examples/ch1-02/hello-c-03/hello-c-03.c b/examples/ch1-02/hello-c-03/hello-c-03.c
deleted file mode 100644
index 8626b30..0000000
--- a/examples/ch1-02/hello-c-03/hello-c-03.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include <stdio.h>
-
-main()
-{
-	printf("hello, world\n");
-}
diff --git a/examples/ch1-02/hello-c-04/hello-c-04.c b/examples/ch1-02/hello-c-04/hello-c-04.c
deleted file mode 100644
index 1aed89f..0000000
--- a/examples/ch1-02/hello-c-04/hello-c-04.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include <stdio.h>
-
-main(void)
-{
-	printf("hello, world\n");
-}
diff --git a/examples/ch1-02/hello-go-200806/hello.go.txt b/examples/ch1-02/hello-go-200806/hello.go.txt
deleted file mode 100644
index ac52ff5..0000000
--- a/examples/ch1-02/hello-go-200806/hello.go.txt
+++ /dev/null
@@ -1,8 +0,0 @@
-// +build ignore
-
-package main
-
-func main() int {
-	print "hello, world\n";
-	return 0;
-}
diff --git a/examples/ch1-02/hello-go-20080627/hello.go.txt b/examples/ch1-02/hello-go-20080627/hello.go.txt
deleted file mode 100644
index f5ddc15..0000000
--- a/examples/ch1-02/hello-go-20080627/hello.go.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-// +build ignore
-
-package main
-
-func main() {
-	print "hello, world\n";
-}
diff --git a/examples/ch1-02/hello-go-20080811/hello.go.txt b/examples/ch1-02/hello-go-20080811/hello.go.txt
deleted file mode 100644
index 67fcaad..0000000
--- a/examples/ch1-02/hello-go-20080811/hello.go.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-package main
-
-func main() {
-	print("hello, world\n");
-}
diff --git a/examples/ch1-02/hello-go-20081024/hello.go.txt b/examples/ch1-02/hello-go-20081024/hello.go.txt
deleted file mode 100644
index 85051d0..0000000
--- a/examples/ch1-02/hello-go-20081024/hello.go.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-// +build ignore
-
-package main
-
-import "fmt"
-
-func main() {
-	fmt.printf("hello, world\n");
-}
diff --git a/examples/ch1-02/hello-go-20090915/hello.go.txt b/examples/ch1-02/hello-go-20090915/hello.go.txt
deleted file mode 100644
index 0cb5e81..0000000
--- a/examples/ch1-02/hello-go-20090915/hello.go.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-// +build ignore
-
-package main
-
-import "fmt"
-
-func main() {
-	fmt.Printf("hello, world\n");
-}
diff --git a/examples/ch1-02/hello-go-20091211/hello.go b/examples/ch1-02/hello-go-20091211/hello.go
deleted file mode 100644
index c2fbf9c..0000000
--- a/examples/ch1-02/hello-go-20091211/hello.go
+++ /dev/null
@@ -1,7 +0,0 @@
-package main
-
-import "fmt"
-
-func main() {
-	fmt.Printf("hello, world\n")
-}
diff --git a/examples/ch1-02/hello-go-asm/hello.go b/examples/ch1-02/hello-go-asm/hello.go
deleted file mode 100644
index 20addf0..0000000
--- a/examples/ch1-02/hello-go-asm/hello.go
+++ /dev/null
@@ -1,6 +0,0 @@
-// Copyright © 2017 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-package main
-
-func main()
diff --git a/examples/ch1-02/hello-go-asm/hello_amd64.s b/examples/ch1-02/hello-go-asm/hello_amd64.s
deleted file mode 100644
index 3bf0038..0000000
--- a/examples/ch1-02/hello-go-asm/hello_amd64.s
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright © 2017 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-#include "textflag.h"
-#include "funcdata.h"
-
-// "Hello World!\n"
-DATA  text<>+0(SB)/8,$"Hello Wo"
-DATA  text<>+8(SB)/8,$"rld!\n"
-GLOBL text<>(SB),NOPTR,$16
-
-// func main()
-TEXT ·main(SB), $16-0
-    NO_LOCAL_POINTERS
-    MOVQ $text<>+0(SB), AX
-    MOVQ AX, (SP)
-    MOVQ $16, 8(SP)
-    CALL runtime·printstring(SB)
-    RET
diff --git a/examples/ch1-02/hello-go-cgo/hello.go b/examples/ch1-02/hello-go-cgo/hello.go
deleted file mode 100644
index f2a04aa..0000000
--- a/examples/ch1-02/hello-go-cgo/hello.go
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright © 2017 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-package main
-
-// #include <stdio.h>
-// #include <stdlib.h>
-import "C"
-import "unsafe"
-
-func main() {
-	msg := C.CString("Hello, World!\n")
-	defer C.free(unsafe.Pointer(msg))
-
-	C.fputs(msg, C.stdout)
-}
diff --git a/examples/ch1-02/hello-go-swig/hello.cc b/examples/ch1-02/hello-go-swig/hello.cc
deleted file mode 100644
index f71d644..0000000
--- a/examples/ch1-02/hello-go-swig/hello.cc
+++ /dev/null
@@ -1,8 +0,0 @@
-// Copyright © 2017 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-#include <iostream>
-
-void SayHello() {
-	std::cout << "Hello, World!" << std::endl;
-}
diff --git a/examples/ch1-02/hello-go-swig/hello.go b/examples/ch1-02/hello-go-swig/hello.go
deleted file mode 100644
index dde2af5..0000000
--- a/examples/ch1-02/hello-go-swig/hello.go
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright © 2017 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-// +build ignore
-
-package main
-
-import (
-	hello "."
-)
-
-func main() {
-	hello.SayHello()
-}
diff --git a/examples/ch1-02/hello-go-swig/hello.swigcxx b/examples/ch1-02/hello-go-swig/hello.swigcxx
deleted file mode 100644
index ac0f3c5..0000000
--- a/examples/ch1-02/hello-go-swig/hello.swigcxx
+++ /dev/null
@@ -1,8 +0,0 @@
-// Copyright © 2017 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-%module main
-
-%inline %{
-extern void SayHello();
-%}
diff --git a/examples/ch1-02/hello-go-v2/hello.go b/examples/ch1-02/hello-go-v2/hello.go
deleted file mode 100644
index 7c2b866..0000000
--- a/examples/ch1-02/hello-go-v2/hello.go
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright © 2017 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-package main
-
-import (
-	"fmt"
-	"log"
-	"net/http"
-	"time"
-)
-
-func main() {
-	fmt.Println("Please visit http://127.0.0.1:12345/")
-	http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
-		s := fmt.Sprintf("你好, 世界! -- Time: %s", time.Now().String())
-		fmt.Fprintf(w, "%v\n", s)
-		log.Printf("%v\n", s)
-	})
-	if err := http.ListenAndServe(":12345", nil); err != nil {
-		log.Fatal("ListenAndServe: ", err)
-	}
-}
diff --git a/examples/ch1-02/hello-limbo/hello.limbo b/examples/ch1-02/hello-limbo/hello.limbo
deleted file mode 100644
index dcd78cb..0000000
--- a/examples/ch1-02/hello-limbo/hello.limbo
+++ /dev/null
@@ -1,15 +0,0 @@
-implement Hello;
-
-include "sys.m"; sys: Sys;
-include "draw.m";
-
-Hello: module
-{
-	init: fn(ctxt: ref Draw->Context, args: list of string);
-};
-
-init(ctxt: ref Draw->Context, args: list of string)
-{
-	sys = load Sys Sys->PATH;
-	sys->print("hello, world\n");
-}
diff --git a/examples/ch1-02/hello-newsqueak/hello.newsqueak b/examples/ch1-02/hello-newsqueak/hello.newsqueak
deleted file mode 100644
index 409e345..0000000
--- a/examples/ch1-02/hello-newsqueak/hello.newsqueak
+++ /dev/null
@@ -1 +0,0 @@
-print("Hello,", "World", "\n");
diff --git a/examples/ch1-02/prime-newsqueak/prime.newsqueak b/examples/ch1-02/prime-newsqueak/prime.newsqueak
deleted file mode 100644
index d915c32..0000000
--- a/examples/ch1-02/prime-newsqueak/prime.newsqueak
+++ /dev/null
@@ -1,41 +0,0 @@
-// 向管道输出从2开始的自然数序列
-counter := prog(c:chan of int) {
-	i := 2;
-	for(;;) {
-		c <-= i++;
-	}
-};
-
-// 针对listen管道获取的数列，过滤掉是prime倍数的数
-// 新的序列输出到send管道
-filter := prog(prime:int, listen, send:chan of int) {
-	i:int;
-	for(;;) {
-		if((i = <-listen)%prime) {
-			send <-= i;
-		}
-	}
-};
-
-// 主函数
-// 每个管道第一个流出的数必然是素数
-// 然后基于这个新的素数构建新的素数过滤器
-sieve := prog() of chan of int {
-	c := mk(chan of int);
-	begin counter(c);
-	prime := mk(chan of int);
-	begin prog(){
-		p:int;
-		newc:chan of int;
-		for(;;){
-			prime <-= p =<- c;
-			newc = mk();
-			begin filter(p, c, newc);
-			c = newc;
-		}
-	}();
-	become prime;
-};
-
-// 启动素数筛
-prime := sieve();