diff --git a/index.html b/index.html
index ee3d256..76ca4e6 100644
--- a/index.html
+++ b/index.html
@@ -2,6 +2,8 @@
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
     <!-- https://gitlab.com/zlax/romans ancient roman numerals -->
+    <!-- background gif by Erica Anderson
+         https://ericaofanderson.tumblr.com/post/679984955933261824 -->
     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
     <title>ancient roman numerals</title>
     <style type="text/css">
