diff --git a/moon.png b/assets/moon.png
old mode 100755
new mode 100644
similarity index 100%
rename from moon.png
rename to assets/moon.png
diff --git a/main.py b/main.py
index 91c1f61..b658bec 100644
--- a/main.py
+++ b/main.py
@@ -180,7 +180,7 @@ class Main:
             new_moon_dt: datetime = ephem.localtime (
                     ephem.previous_new_moon (observer_with_time.date))
             moon_days_old: float = (
-                    (datetime.now () -  new_moon_dt).total_seconds ()
+                    (datetime.now () - new_moon_dt).total_seconds ()
                     / 60 / 60 / 24)
 
             # 背景描画
diff --git a/test.py b/test.py
index 6b986a2..0730305 100644
--- a/test.py
+++ b/test.py
@@ -7,7 +7,9 @@ from enum import Enum, auto
 from typing import Callable, TypedDict
 
 import cv2
+import ephem  # type: ignore
 import pygame
+import pygame.gfxdraw
 from cv2 import VideoCapture
 from ephem import Moon, Observer, Sun  # type: ignore
 from pygame import Rect, Surface
@@ -482,22 +484,50 @@ class Jojoko (GameObject):
     大月ヨヨコ
 
     Attributes:
-        phase (float):  月齢
+        base (Surface):     満月ヨヨコ Surface
+        moon (Moon):        ephem の月オブゼクト
+        surface (Surface):  缺けたヨヨコ Surface
     """
 
-    phase:  float
+    base:       Surface
+    moon:       Moon
 
     def __init__ (
             self,
             game:   Game,
     ):
-        ...
+        super ().__init__ (game)
+        self.base = pygame.transform.scale (pygame.image.load ('assets/moon.png'), (200, 200))
 
     def redraw (
             self,
     ) -> None:
         ...
 
+    @property
+    def phase (
+            self,
+    ) -> float:
+        dt: datetime = ephem.localtime (ephem.previous_new_moon (self.game.sky.observer.date))
+        return (datetime.now () - dt).total_seconds () / 60 / 60 / 24
+
+    @property
+    def surface (
+            self,
+    ) -> Surface:
+        jojoko = self.base.copy ()
+        jojoko.set_colorkey ((0, 255, 0))
+        for i in range (200):
+            if 1 <= self.phase < 15:
+                pygame.gfxdraw.bezier (jojoko, ((0, 100 + i), (100, 180 * self.phase / 7 - 80 + i), (200, 100 + i)), 3, (0, 255, 0))
+            elif self.phase < 16:
+                pass
+            elif self.phase < 30:
+                pygame.gfxdraw.bezier (jojoko, ((0, 100 - i), (100, 180 * (self.phase - 15) / 7 - 80 - i), (200, 100 - i)), 3, (0, 255, 0))
+            else:
+                jojoko.fill ((0, 255, 0))
+        return jojoko
+
 
 class Sky:
     """