More videos re the debugger

src/using/debugger.md

@@ -1,4 +1,13 @@
 # Debugger
 TLA+ tools come with a debugger that allow you to debug your specifications. See it in action:
 
-<iframe width="1333" height="485" src="https://www.youtube.com/embed/x6u8LYSso6s" title="TLA+ Debugger:  Force violation of artificial invariant with &#39;violate&#39; debugger command" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+<iframe width="1333" height="485" src="https://www.youtube.com/embed/x6u8LYSso6s" title="TLA+ Debugger:  Force violation of artificial invariant with &#39;violate&#39; debugger command" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+
+<iframe width="1917" height="806" src="https://www.youtube.com/embed/DsfbdsE4hJ0" title="The TLA+ Debugger" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+
+
+## graphical and time-traveling debugging
+You will need the SVG extension: [https://marketplace.visualstudio.com/items?itemName=jock.svg](https://marketplace.visualstudio.com/items?itemName=jock.svg).
+
+<iframe width="1917" height="806" src="https://www.youtube.com/embed/IO9ik850i0M" title="Graphical and time-traveling debugging for TLA+" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
+