This PowerPoint uses a tone ladder. Each click of the mouse adds solfege starting with mi then re then do. With another click a question mark appears on the bottom step as a "mystery note." A few other clicks adds more steps above to include la at the top of the set of steps. You may wish to stop there if low la has not yet been presented. If you have, a couple more clicks removes the question mark and adds "la," to the bottom step.