The following animations are written as a Excel spreadsheets. If you click on the button you will open a Word document that has the spreadsheet embedded in it. Open this document, right click in an inoffensive place and select Worksheet Object > Edit. That opens the embedded spreadsheet. Save this to your own computer as a spreadsheet. Then open this saved version.  To animate a graph, click on an empty cell and use Ctrl-f (forwards), Ctrl-b (backwards) or Ctrl-r (run), depending on which model you are looking at. When asked, you have to allow embedded macros, because the animation requires them.