diff --git a/media/blackhole.png b/media/blackhole.png
new file mode 100644
index 0000000..3cbdbf6
--- /dev/null
+++ b/media/blackhole.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:da17a1a2933d19b55a05c4a2783d3298da7226bb09317600de2c3f119d0cdf6b
+size 330723
diff --git a/style/cube.css b/style/cube.css
index aa3a350..a1ea141 100644
--- a/style/cube.css
+++ b/style/cube.css
@@ -114,7 +114,7 @@
   #cube {
     position: relative;
 
-    > section {
+    > section, &::after {
       position: absolute;
       inset: 5vh 5vw;
       overflow: auto;
@@ -128,6 +128,14 @@
     }
   }
 
+  #outer::after {
+    content: ' ';
+    position: absolute;
+    inset: 0;
+    background: url(../media/blackhole.png) center / 60% no-repeat;
+    transform: translateZ(var(--nhalf));
+  }
+
   @keyframes breathe {
     40% { transform: var(--base-transform) translateZ(var(--breathe)); }
   }