(Originally posted on Doug's MATLAB Video Tutorials blog.)

This was a question that came across my desk recently: "How do I know what figure numbers are already open?" The way to answer this is to query the "root" (always handle 0) for its children. Figures are always children of the root and are the only direct children of the root. get(0, 'children') This video discusses the question in more depth and talks about the graphics family tree.