diff --git a/site/index.html b/site/index.html
index 06108b8..00f5a6f 100644
--- a/site/index.html
+++ b/site/index.html
@@ -368,7 +368,7 @@ <h1>Snap blocks together, and watch the tortoise draw.</h1>
 
     <figure class="video">
       <iframe width="560" height="315"
-              src="https://www.youtube-nocookie.com/embed/BG4qyHeimHE"
+              src="https://www.youtube-nocookie.com/embed/3lmWw37Da-U"
               title="YouTube video player" frameborder="0"
               allow="accelerometer; autoplay; clipboard-write; encrypted-media;
                      gyroscope; picture-in-picture; web-share"
@@ -594,7 +594,7 @@ <h1>ブロックをならべて、カメに絵をかいてもらおう！</h1>
 
     <figure class="video">
       <iframe width="560" height="315"
-              src="https://www.youtube-nocookie.com/embed/BG4qyHeimHE"
+              src="https://www.youtube-nocookie.com/embed/3lmWw37Da-U"
               title="YouTube video player" frameborder="0"
               allow="accelerometer; autoplay; clipboard-write; encrypted-media;
                      gyroscope; picture-in-picture; web-share"