diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index a3509c1..a22a93c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.0)
 
 include_directories(core)
-include_directories(common)
+include_directories(utils)
 include_directories(all_cases)
 
 include_directories(raw_code)
@@ -9,7 +9,7 @@ include_directories(short_code)
 include_directories(common_code)
 
 add_subdirectory(core)
-add_subdirectory(common)
+add_subdirectory(utils)
 add_subdirectory(all_cases)
 
 add_subdirectory(raw_code)
@@ -20,7 +20,7 @@ add_subdirectory(common_code)
 add_executable(klotski main.cc fast_cal.cc)
 
 target_link_libraries(klotski core)
-target_link_libraries(klotski common)
+target_link_libraries(klotski utils)
 target_link_libraries(klotski all_cases)
 
 target_link_libraries(klotski raw_code)
diff --git a/src/all_cases/CMakeLists.txt b/src/all_cases/CMakeLists.txt
index cfcce31..29a672f 100644
--- a/src/all_cases/CMakeLists.txt
+++ b/src/all_cases/CMakeLists.txt
@@ -1,4 +1,4 @@
 cmake_minimum_required(VERSION 3.0)
 
-add_library(all_cases basic_ranges.cc all_cases.cc)
-target_link_libraries(all_cases common)
+add_library(all_cases all_cases.cc basic_ranges.cc)
+target_link_libraries(all_cases utils)
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
deleted file mode 100644
index 73c0316..0000000
--- a/src/common/CMakeLists.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-cmake_minimum_required(VERSION 3.0)
-
-add_library(common common.cc)
-target_link_libraries(common short_code)
diff --git a/src/common/common.h b/src/common/common.h
deleted file mode 100644
index 8c80a6c..0000000
--- a/src/common/common.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-
-#include <cstdint>
-
-class Common {
-public:
-    static uint32_t range_reverse(uint32_t bin);
-    static bool check_case(uint32_t head, uint32_t range);
-};
diff --git a/src/common_code/CMakeLists.txt b/src/common_code/CMakeLists.txt
index 5b861e0..7b6d129 100644
--- a/src/common_code/CMakeLists.txt
+++ b/src/common_code/CMakeLists.txt
@@ -1,4 +1,4 @@
 cmake_minimum_required(VERSION 3.0)
 
 add_library(common_code common_code.cc)
-target_link_libraries(common_code common)
+target_link_libraries(common_code utils)
diff --git a/src/core/core.cc b/src/core/core.cc
index 00d12fb..a10859f 100644
--- a/src/core/core.cc
+++ b/src/core/core.cc
@@ -1,5 +1,5 @@
 #include "core.h"
-#include "raw_code.h"
+#include "common.h"
 
 #define ALLOW_UP    (filter != -UP)
 #define ALLOW_DOWN  (filter != -DOWN)
diff --git a/src/core/core.h b/src/core/core.h
index 4272cc9..c55de41 100644
--- a/src/core/core.h
+++ b/src/core/core.h
@@ -7,16 +7,6 @@
 #define DOWN  (+12) // +4 * 3-bits
 #define RIGHT  (+3) // +1 * 3-bits
 
-#define F_1x1 (uint64_t)0x7 // 111
-#define F_1x2 (uint64_t)0x3F // 111 111
-#define F_2x1 (uint64_t)0x7007 // 111 000 000 000 111
-#define F_2x2 (uint64_t)0x3F03F // 111 111 000 000 111 111
-
-#define F_1x1_R (uint64_t)0x38 // 111 000
-#define F_1x1_D (uint64_t)0x7000 // 111 000 000 000 000
-#define F_2x1_R (uint64_t)0x38038 // 111 000 000 000 111 000
-#define F_1x2_D (uint64_t)0x3F000 // 111 111 000 000 000 000
-
 class Core {
 public:
     void next_step(uint64_t code, uint64_t mask);
diff --git a/src/fast_cal.cc b/src/fast_cal.cc
index df5b749..0066462 100644
--- a/src/fast_cal.cc
+++ b/src/fast_cal.cc
@@ -4,6 +4,7 @@
 #include "core.h"
 #include "fast_cal.h"
 #include "raw_code.h"
+#include "common.h"
 
 struct fast_cal_t {
     uint64_t code;
diff --git a/src/raw_code/CMakeLists.txt b/src/raw_code/CMakeLists.txt
index 72c5f65..e7863a0 100644
--- a/src/raw_code/CMakeLists.txt
+++ b/src/raw_code/CMakeLists.txt
@@ -1,4 +1,4 @@
 cmake_minimum_required(VERSION 3.0)
 
 add_library(raw_code raw_code.cc)
-target_link_libraries(raw_code common common_code)
+target_link_libraries(raw_code utils common_code)
diff --git a/src/raw_code/raw_code.h b/src/raw_code/raw_code.h
index eec1f47..b83e469 100644
--- a/src/raw_code/raw_code.h
+++ b/src/raw_code/raw_code.h
@@ -3,18 +3,6 @@
 #include <cstdint>
 #include "common_code.h"
 
-#define B_space 0b000
-#define B_fill  0b111
-#define B_1x2   0b001
-#define B_2x1   0b010
-#define B_1x1   0b011
-#define B_2x2   0b100
-
-#define C_1x1 (uint64_t)0x3 // 011
-#define C_1x2 (uint64_t)0x39 // 111 001
-#define C_2x1 (uint64_t)0x7002 // 111 000 000 000 010
-#define C_2x2 (uint64_t)0x3F03C // 111 111 000 000 111 100
-
 class CommonCode;
 
 class RawCode {
diff --git a/src/short_code/CMakeLists.txt b/src/short_code/CMakeLists.txt
index 4ff6086..ae2dfcc 100644
--- a/src/short_code/CMakeLists.txt
+++ b/src/short_code/CMakeLists.txt
@@ -1,4 +1,4 @@
 cmake_minimum_required(VERSION 3.0)
 
 add_library(short_code convert.cc short_code.cc data_loader.cc)
-target_link_libraries(short_code common all_cases)
+target_link_libraries(short_code utils all_cases)
diff --git a/src/utils/CMakeLists.txt b/src/utils/CMakeLists.txt
new file mode 100644
index 0000000..c3481e7
--- /dev/null
+++ b/src/utils/CMakeLists.txt
@@ -0,0 +1,4 @@
+cmake_minimum_required(VERSION 3.0)
+
+add_library(utils common.cc)
+target_link_libraries(utils short_code)
diff --git a/src/common/common.cc b/src/utils/common.cc
similarity index 100%
rename from src/common/common.cc
rename to src/utils/common.cc
diff --git a/src/utils/common.h b/src/utils/common.h
new file mode 100644
index 0000000..e90ed90
--- /dev/null
+++ b/src/utils/common.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <cstdint>
+
+#define B_space 0b000
+#define B_fill  0b111
+#define B_1x2   0b001
+#define B_2x1   0b010
+#define B_1x1   0b011
+#define B_2x2   0b100
+
+#define C_1x1 (uint64_t)0x3 // 011
+#define C_1x2 (uint64_t)0x39 // 111 001
+#define C_2x1 (uint64_t)0x7002 // 111 000 000 000 010
+#define C_2x2 (uint64_t)0x3F03C // 111 111 000 000 111 100
+
+#define F_1x1 (uint64_t)0x7 // 111
+#define F_1x2 (uint64_t)0x3F // 111 111
+#define F_2x1 (uint64_t)0x7007 // 111 000 000 000 111
+#define F_2x2 (uint64_t)0x3F03F // 111 111 000 000 111 111
+
+#define F_1x1_R (uint64_t)0x38 // 111 000
+#define F_1x1_D (uint64_t)0x7000 // 111 000 000 000 000
+#define F_2x1_R (uint64_t)0x38038 // 111 000 000 000 111 000
+#define F_1x2_D (uint64_t)0x3F000 // 111 111 000 000 000 000
+
+class Common {
+public:
+    static uint32_t range_reverse(uint32_t bin);
+    static bool check_case(uint32_t head, uint32_t range);
+};