diff --git a/iap21.md b/iap21.md
index 0a41bd74a..229ae1d6d 100644
--- a/iap21.md
+++ b/iap21.md
@@ -72,6 +72,7 @@
   - who are the [[audiences]]?
 - other interesting references
   - [[protocols.io]]
+  - [[shader toy]]
 
 
 ## [[2021-01-27]]