Fix example code

Author: yuanchuan

src/examples.js

@@ -617,7 +617,7 @@ export default {
       path {
         stroke: #1B2D37;
         fill: none;
-        d: M 0 0 T 0 @m120.n(*@pn(@m4(.2), @m4(-.2))) 0;
+        d: M 0 0 T 0 @m120.n(*@pn(@m4(.2), @m4(-.2))) 24;
         draw: 10s;
       }
     }