diff --git a/doc/sandbox.mdwn b/doc/sandbox.mdwn
index 4a80db78d..40a554a91 100644
--- a/doc/sandbox.mdwn
+++ b/doc/sandbox.mdwn
@@ -1,6 +1,6 @@
 Hello, world!
 
-test...id Morjo
+test...id Morjo $\sin(x)$
 
 This is the [[SandBox]], a page anyone can edit to try out ikiwiki
 (version [[!version  ]]).