I would suggest moving everything from the inner (main) folder out into the outer folder (New Super Mario Bros. Greenfoot). Also, remove the PowerPoint files from within the 'images' folder'.

Alternative possibility toggling changed to "qwerty" keys below number key (since function keys do not work well on this site.

@Hippo, I could probably determine the chord length of a completed line and, instead of moving (or drawing) 5 pixels at a time, move (draw) the entire chord length each act step. I would think that would help for the visual on the site.

@Hippo, that is top speed -- right? Believable. However, in the greenfoot application, it runs SO much quicker (probably 20 to 30 or more times quicker). The visual effect is greatly enhanced..